#
f4f346c3 |
| 01-Aug-2025 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'perf-tools-for-v6.17-2025-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools
Pull perf tools updates from Namhyung Kim: "Build-ID processing goodies:
Build-IDs
Merge tag 'perf-tools-for-v6.17-2025-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools
Pull perf tools updates from Namhyung Kim: "Build-ID processing goodies:
Build-IDs are content based hashes to link regions of memory to ELF files in post processing. They have been available in distros for quite a while:
$ file /bin/bash /bin/bash: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=707a1c670cd72f8e55ffedfbe94ea98901b7ce3a, for GNU/Linux 3.2.0, stripped
It is possible to ask the kernel to get it from mmap executable backing storage at time they are being put in place and send it as metadata at that moment to have in perf.data.
Prefer that across the board to speed up 'record' time - it post processes the samples to find binaries touched by any samples and to save them with build-ID. It can skip reading build-ID in userspace if it comes from the kernel.
perf record:
* Make --buildid-mmap default. The kernel can generate MMAP2 events with a build-ID from ELF header. Use that by default instead of using inode and device ID to identify binaries. It also can be disabled with --no-buildid-mmap.
* Use BPF for -u/--uid option to sample processes belong to a user. BPF can track user processes more accurately and the existing logic often fails to get the list of processes due to race with reading the /proc filesystem.
* Generate PERF_RECORD_BPF_METADATA when it profiles BPF programs and they have variables starting with "bpf_metadata_". This will help to identify BPF objects used in the profile. This has been supported in bpftool for some time and allows the recording of metadata such as commit hashes, versions, etc, that now gets recorded in perf.data as well.
* Collect list of DSOs touched in the sample callchains as well as in the sample itself. This would increase the processing time at the end of record, but can improve the data quality.
perf stat:
* Add a new 'drm' pseudo-PMU support like in 'hwmon'. It can collect DRM usage stats using fdinfo in /proc.
On my Intel laptop, it shows like below:
$ perf list drm ...
drm: drm-active-stolen-system0 [Total memory active in one or more engines. Unit: drm_i915] drm-active-system0 [Total memory active in one or more engines. Unit: drm_i915] drm-engine-capacity-video [Engine capacity. Unit: drm_i915] drm-engine-copy [Utilization in ns. Unit: drm_i915] drm-engine-render [Utilization in ns. Unit: drm_i915] drm-engine-video [Utilization in ns. Unit: drm_i915] ...
$ sudo perf stat -a -e drm-engine-render,drm-engine-video,drm-engine-capacity-video sleep 1
Performance counter stats for 'system wide':
48,137,316,988,873 ns drm-engine-render 34,452,696,746 ns drm-engine-video 20 capacity drm-engine-capacity-video
1.002086194 seconds time elapsed
perf list
* Add description for software events. The description is in JSON format and the event parser now can handle the software events like others (for example, it's case-insensitive and subject to wildcard matching).
$ perf list software
List of pre-defined events (to be used in -e or -M):
software: alignment-faults [Number of kernel handled memory alignment faults. Unit: software] bpf-output [An event used by BPF programs to write to the perf ring buffer. Unit: software] cgroup-switches [Number of context switches to a task in a different cgroup. Unit: software] context-switches [Number of context switches [This event is an alias of cs]. Unit: software] cpu-clock [Per-CPU high-resolution timer based event. Unit: software] cpu-migrations [Number of times a process has migrated to a new CPU [This event is an alias of migrations]. Unit: software] cs [Number of context switches [This event is an alias of context-switches]. Unit: software] dummy [A placeholder event that doesn't count anything. Unit: software] emulation-faults [Number of kernel handled unimplemented instruction faults handled through emulation. Unit: software] faults [Number of page faults [This event is an alias of page-faults]. Unit: software] major-faults [Number of major page faults. Major faults require I/O to handle. Unit: software] migrations [Number of times a process has migrated to a new CPU [This event is an alias of cpu-migrations]. Unit: software] minor-faults [Number of minor page faults. Minor faults don't require I/O to handle. Unit: software] page-faults [Number of page faults [This event is an alias of faults]. Unit: software] task-clock [Per-task high-resolution timer based event. Unit: software]
perf ftrace:
* Add -e/--events option to perf ftrace latency to measure latency between the two events instead of a function.
$ sudo perf ftrace latency -ab -e i915_request_wait_begin,i915_request_wait_end --hide-empty -- sleep 1 # DURATION | COUNT | GRAPH | 256 - 512 us | 4 | ###### | 2 - 4 ms | 2 | ### | 4 - 8 ms | 12 | ################### | 8 - 16 ms | 10 | ################ |
# statistics (in usec) total time: 194915 avg time: 6961 max time: 12855 min time: 373 count: 28
* Add new function graph tracer options (--graph-opts) to display more info like arguments and return value. They will be passed to the kernel ftrace directly.
$ sudo perf ftrace -G vfs_write --graph-opts retval,retaddr # tracer: function_graph # # CPU DURATION FUNCTION CALLS # | | | | | | | ... 5) | mutex_unlock() { /* <-rb_simple_write+0xda/0x150 */ 5) 0.188 us | local_clock(); /* <-lock_release+0x2ad/0x440 ret=0x3bf2a3cf90e */ 5) | rt_mutex_slowunlock() { /* <-rb_simple_write+0xda/0x150 */ 5) | _raw_spin_lock_irqsave() { /* <-rt_mutex_slowunlock+0x4f/0x200 */ 5) 0.123 us | preempt_count_add(); /* <-_raw_spin_lock_irqsave+0x23/0x90 ret=0x0 */ 5) 0.128 us | local_clock(); /* <-__lock_acquire.isra.0+0x17a/0x740 ret=0x3bf2a3cfc8b */ 5) 0.086 us | do_raw_spin_trylock(); /* <-_raw_spin_lock_irqsave+0x4a/0x90 ret=0x1 */ 5) 0.845 us | } /* _raw_spin_lock_irqsave ret=0x292 */ ...
Misc:
* Add perf archive --exclude-buildids <FILE> option to skip some binaries. The format of the FILE should be same as an output of perf buildid-list.
* Get rid of dependency of libcrypto. It was just to get SHA-1 hash so implement it directly like in the kernel. A side effect is that it needs -fno-strict-aliasing compiler option (again, like in the kernel).
* Convert all shell script tests to use bash"
* tag 'perf-tools-for-v6.17-2025-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (179 commits) perf record: Cache build-ID of hit DSOs only perf test: Ensure lock contention using pipe mode perf python: Stop using deprecated PyUnicode_AsString() perf list: Skip ABI PMUs when printing pmu values perf list: Remove tracepoint printing code perf tp_pmu: Add event APIs perf tp_pmu: Factor existing tracepoint logic to new file perf parse-events: Remove non-json software events perf jevents: Add common software event json perf tools: Remove libtraceevent in .gitignore perf test: Fix comment ordering perf sort: Use perf_env to set arch sort keys and header perf test: Move PERF_SAMPLE_WEIGHT_STRUCT parsing to common test perf sample: Remove arch notion of sample parsing perf env: Remove global perf_env perf trace: Avoid global perf_env with evsel__env perf auxtrace: Pass perf_env from session through to mmap read perf machine: Explicitly pass in host perf_env perf bench synthesize: Avoid use of global perf_env perf top: Make perf_env locally scoped ...
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Revision tags: v6.16 |
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#
5b11409b |
| 24-Jul-2025 |
Ian Rogers <irogers@google.com> |
perf jitdump: Directly mark the jitdump DSO
The DSO being generated was being accessed through a thread's maps, this is unnecessary as the dso can just be directly found. This avoids problems with p
perf jitdump: Directly mark the jitdump DSO
The DSO being generated was being accessed through a thread's maps, this is unnecessary as the dso can just be directly found. This avoids problems with passing a NULL evsel which may be inspected to determine properties of a callchain when using the buildid DSO marking code.
Signed-off-by: Ian Rogers <irogers@google.com> Link: https://lore.kernel.org/r/20250724163302.596743-8-irogers@google.com Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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Revision tags: v6.16-rc7, v6.16-rc6, v6.16-rc5, v6.16-rc4, v6.16-rc3, v6.16-rc2, v6.16-rc1 |
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#
4f978603 |
| 02-Jun-2025 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge branch 'next' into for-linus
Prepare input updates for 6.16 merge window.
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#
bbfd5594 |
| 28-May-2025 |
Joonas Lahtinen <joonas.lahtinen@linux.intel.com> |
Merge drm/drm-next into drm-intel-gt-next
Need to pull in a67221b5eb8d ("drm/i915/dp: Return min bpc supported by source instead of 0") in order to fix build breakage on GCC 9.4.0 (from Ubuntu 20.04
Merge drm/drm-next into drm-intel-gt-next
Need to pull in a67221b5eb8d ("drm/i915/dp: Return min bpc supported by source instead of 0") in order to fix build breakage on GCC 9.4.0 (from Ubuntu 20.04).
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
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Revision tags: v6.15, v6.15-rc7 |
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#
db5302ae |
| 16-May-2025 |
Jani Nikula <jani.nikula@intel.com> |
Merge drm/drm-next into drm-intel-next
Backmerge to sync with v6.15-rc, xe, and specifically async flip changes in drm-misc.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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#
d51b9d81 |
| 15-May-2025 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge tag 'v6.15-rc6' into next
Sync up with mainline to bring in xpad controller changes.
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Revision tags: v6.15-rc6, v6.15-rc5 |
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#
844e31bb |
| 29-Apr-2025 |
Rob Clark <robdclark@chromium.org> |
Merge remote-tracking branch 'drm-misc/drm-misc-next' into msm-next
Merge drm-misc-next to get commit Fixes: fec450ca15af ("drm/display: hdmi: provide central data authority for ACR params").
Signe
Merge remote-tracking branch 'drm-misc/drm-misc-next' into msm-next
Merge drm-misc-next to get commit Fixes: fec450ca15af ("drm/display: hdmi: provide central data authority for ACR params").
Signed-off-by: Rob Clark <robdclark@chromium.org>
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Revision tags: v6.15-rc4 |
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#
3ab7ae8e |
| 24-Apr-2025 |
Thomas Hellström <thomas.hellstrom@linux.intel.com> |
Merge drm/drm-next into drm-xe-next
Backmerge to bring in linux 6.15-rc.
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
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Revision tags: v6.15-rc3, v6.15-rc2 |
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#
9f13acb2 |
| 11-Apr-2025 |
Ingo Molnar <mingo@kernel.org> |
Merge tag 'v6.15-rc1' into x86/cpu, to refresh the branch with upstream changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
6ce0fdaa |
| 09-Apr-2025 |
Ingo Molnar <mingo@kernel.org> |
Merge tag 'v6.15-rc1' into x86/asm, to refresh the branch
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
1260ed77 |
| 08-Apr-2025 |
Thomas Zimmermann <tzimmermann@suse.de> |
Merge drm/drm-fixes into drm-misc-fixes
Backmerging to get updates from v6.15-rc1.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
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#
1afba39f |
| 07-Apr-2025 |
Thomas Zimmermann <tzimmermann@suse.de> |
Merge drm/drm-next into drm-misc-next
Backmerging to get v6.15-rc1 into drm-misc-next. Also fixes a build issue when enabling CONFIG_DRM_SCHED_KUNIT_TEST.
Signed-off-by: Thomas Zimmermann <tzimmerm
Merge drm/drm-next into drm-misc-next
Backmerging to get v6.15-rc1 into drm-misc-next. Also fixes a build issue when enabling CONFIG_DRM_SCHED_KUNIT_TEST.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
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Revision tags: v6.15-rc1 |
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#
946661e3 |
| 05-Apr-2025 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge branch 'next' into for-linus
Prepare input updates for 6.15 merge window.
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#
802f0d58 |
| 31-Mar-2025 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'perf-tools-for-v6.15-2025-03-27' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools
Pull perf tools updates from Namhyung Kim: "perf record:
- Introduce latency profili
Merge tag 'perf-tools-for-v6.15-2025-03-27' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools
Pull perf tools updates from Namhyung Kim: "perf record:
- Introduce latency profiling using scheduler information.
The latency profiling is to show impacts on wall-time rather than cpu-time. By tracking context switches, it can weight samples and find which part of the code contributed more to the execution latency.
The value (period) of the sample is weighted by dividing it by the number of parallel execution at the moment. The parallelism is tracked in perf report with sched-switch records. This will reduce the portion that are run in parallel and in turn increase the portion of serial executions.
For now, it's limited to profile processes, IOW system-wide profiling is not supported. You can add --latency option to enable this.
$ perf record --latency -- make -C tools/perf
I've run the above command for perf build which adds -j option to make with the number of CPUs in the system internally. Normally it'd show something like below:
$ perf report -F overhead,comm ... # # Overhead Command # ........ ............... # 78.97% cc1 6.54% python3 4.21% shellcheck 3.28% ld 1.80% as 1.37% cc1plus 0.80% sh 0.62% clang 0.56% gcc 0.44% perl 0.39% make ...
The cc1 takes around 80% of the overhead as it's the actual compiler. However it runs in parallel so its contribution to latency may be less than that. Now, perf report will show both overhead and latency (if --latency was given at record time) like below:
$ perf report -s comm ... # # Overhead Latency Command # ........ ........ ............... # 78.97% 48.66% cc1 6.54% 25.68% python3 4.21% 0.39% shellcheck 3.28% 13.70% ld 1.80% 2.56% as 1.37% 3.08% cc1plus 0.80% 0.98% sh 0.62% 0.61% clang 0.56% 0.33% gcc 0.44% 1.71% perl 0.39% 0.83% make ...
You can see latency of cc1 goes down to around 50% and python3 and ld contribute a lot more than their overhead. You can use --latency option in perf report to get the same result but ordered by latency.
$ perf report --latency -s comm
perf report:
- As a side effect of the latency profiling work, it adds a new output field 'latency' and a sort key 'parallelism'. The below is a result from my system with 64 CPUs. The build was well-parallelized but contained some serial portions.
$ perf report -s parallelism ... # # Overhead Latency Parallelism # ........ ........ ........... # 16.95% 1.54% 62 13.38% 1.24% 61 12.50% 70.47% 1 11.81% 1.06% 63 7.59% 0.71% 60 4.33% 12.20% 2 3.41% 0.33% 59 2.05% 0.18% 64 1.75% 1.09% 9 1.64% 1.85% 5 ...
- Support Feodra mini-debuginfo which is a LZMA compressed symbol table inside ".gnu_debugdata" ELF section.
perf annotate:
- Add --code-with-type option to enable data-type profiling with the usual annotate output.
Instead of focusing on data structure, it shows code annotation together with data type it accesses in case the instruction refers to a memory location (and it was able to resolve the target data type). Currently it only works with --stdio.
$ perf annotate --stdio --code-with-type ... Percent | Source code & Disassembly of vmlinux for cpu/mem-loads,ldlat=30/pp (18 samples, percent: local period) ---------------------------------------------------------------------------------------------------------------------- : 0 0xffffffff81050610 <__fdget>: 0.00 : ffffffff81050610: callq 0xffffffff81c01b80 <__fentry__> # data-type: (stack operation) 0.00 : ffffffff81050615: pushq %rbp # data-type: (stack operation) 0.00 : ffffffff81050616: movq %rsp, %rbp 0.00 : ffffffff81050619: pushq %r15 # data-type: (stack operation) 0.00 : ffffffff8105061b: pushq %r14 # data-type: (stack operation) 0.00 : ffffffff8105061d: pushq %rbx # data-type: (stack operation) 0.00 : ffffffff8105061e: subq $0x10, %rsp 0.00 : ffffffff81050622: movl %edi, %ebx 0.00 : ffffffff81050624: movq %gs:0x7efc4814(%rip), %rax # 0x14e40 <current_task> # data-type: struct task_struct* +0 0.00 : ffffffff8105062c: movq 0x8d0(%rax), %r14 # data-type: struct task_struct +0x8d0 (files) 0.00 : ffffffff81050633: movl (%r14), %eax # data-type: struct files_struct +0 (count.counter) 0.00 : ffffffff81050636: cmpl $0x1, %eax 0.00 : ffffffff81050639: je 0xffffffff810506a9 <__fdget+0x99> 0.00 : ffffffff8105063b: movq 0x20(%r14), %rcx # data-type: struct files_struct +0x20 (fdt) 0.00 : ffffffff8105063f: movl (%rcx), %eax # data-type: struct fdtable +0 (max_fds) 0.00 : ffffffff81050641: cmpl %ebx, %eax 0.00 : ffffffff81050643: jbe 0xffffffff810506ef <__fdget+0xdf> 0.00 : ffffffff81050649: movl %ebx, %r15d 5.56 : ffffffff8105064c: movq 0x8(%rcx), %rdx # data-type: struct fdtable +0x8 (fd) ...
The "# data-type:" part was added with this change. The first few entries are not very interesting. But later you can it accesses a couple of fields in the task_struct, files_struct and fdtable.
perf trace:
- Support syscall tracing for different ABI. For example it can trace system calls for 32-bit applications on 64-bit kernel transparently.
- Add --summary-mode=total option to show global syscall summary. The default is 'thread' to show per-thread syscall summary.
Python support:
- Add more interfaces to 'perf' module to parse events, and config, enable or disable the event list properly so that it can implement basic functionalities purely in Python. There is an example code for these new interfaces in python/tracepoint.py.
- Add mypy and pylint support to enable build time checking. Fix some code based on the findings from these tools.
Internals:
- Introduce io_dir__readdir() API to make directory traveral (usually for proc or sysfs) efficient with less memory footprint.
JSON vendor events:
- Add events and metrics for ARM Neoverse N3 and V3
- Update events and metrics on various Intel CPUs
- Add/update events for a number of SiFive processors"
* tag 'perf-tools-for-v6.15-2025-03-27' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (229 commits) perf bpf-filter: Fix a parsing error with comma perf report: Fix a memory leak for perf_env on AMD perf trace: Fix wrong size to bpf_map__update_elem call perf tools: annotate asm_pure_loop.S perf python: Fix setup.py mypy errors perf test: Address attr.py mypy error perf build: Add pylint build tests perf build: Add mypy build tests perf build: Rename TEST_LOGS to SHELL_TEST_LOGS tools/build: Don't pass test log files to linker perf bench sched pipe: fix enforced blocking reads in worker_thread perf tools: Fix is_compat_mode build break in ppc64 perf build: filter all combinations of -flto for libperl perf vendor events arm64 AmpereOneX: Fix frontend_bound calculation perf vendor events arm64: AmpereOne/AmpereOneX: Mark LD_RETIRED impacted by errata perf trace: Fix evlist memory leak perf trace: Fix BTF memory leak perf trace: Make syscall table stable perf syscalltbl: Mask off ABI type for MIPS system calls perf build: Remove Makefile.syscalls ...
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#
b3cc7428 |
| 26-Mar-2025 |
Jiri Kosina <jkosina@suse.com> |
Merge branch 'for-6.15/amd_sfh' into for-linus
From: Mario Limonciello <mario.limonciello@amd.com>
Some platforms include a human presence detection (HPD) sensor. When enabled and a user is detecte
Merge branch 'for-6.15/amd_sfh' into for-linus
From: Mario Limonciello <mario.limonciello@amd.com>
Some platforms include a human presence detection (HPD) sensor. When enabled and a user is detected a wake event will be emitted from the sensor fusion hub that software can react to.
Example use cases are "wake from suspend on approach" or to "lock when leaving".
This is currently enabled by default on supported systems, but users can't control it. This essentially means that wake on approach is enabled which is a really surprising behavior to users that don't expect it.
Instead of defaulting to enabled add a sysfs knob that users can use to enable the feature if desirable and set it to disabled by default.
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Revision tags: v6.14, v6.14-rc7, v6.14-rc6, v6.14-rc5 |
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#
0410c612 |
| 28-Feb-2025 |
Lucas De Marchi <lucas.demarchi@intel.com> |
Merge drm/drm-next into drm-xe-next
Sync to fix conlicts between drm-xe-next and drm-intel-next.
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
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#
0b119045 |
| 26-Feb-2025 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge tag 'v6.14-rc4' into next
Sync up with the mainline.
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Revision tags: v6.14-rc4, v6.14-rc3, v6.14-rc2, v6.14-rc1, v6.13 |
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#
dc6d2bc2 |
| 13-Jan-2025 |
Ian Rogers <irogers@google.com> |
perf sample: Make user_regs and intr_regs optional
The struct dump_regs contains 512 bytes of cache_regs, meaning the two values in perf_sample contribute 1088 bytes of its total 1384 bytes size. In
perf sample: Make user_regs and intr_regs optional
The struct dump_regs contains 512 bytes of cache_regs, meaning the two values in perf_sample contribute 1088 bytes of its total 1384 bytes size. Initializing this much memory has a cost reported by Tavian Barnes <tavianator@tavianator.com> as about 2.5% when running `perf script --itrace=i0`: https://lore.kernel.org/lkml/d841b97b3ad2ca8bcab07e4293375fb7c32dfce7.1736618095.git.tavianator@tavianator.com/
Adrian Hunter <adrian.hunter@intel.com> replied that the zero initialization was necessary and couldn't simply be removed.
This patch aims to strike a middle ground of still zeroing the perf_sample, but removing 79% of its size by make user_regs and intr_regs optional pointers to zalloc-ed memory. To support the allocation accessors are created for user_regs and intr_regs. To support correct cleanup perf_sample__init and perf_sample__exit functions are created and added throughout the code base.
Signed-off-by: Ian Rogers <irogers@google.com> Link: https://lore.kernel.org/r/20250113194345.1537821-1-irogers@google.com Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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#
93c7dd1b |
| 06-Feb-2025 |
Maxime Ripard <mripard@kernel.org> |
Merge drm/drm-next into drm-misc-next
Bring rc1 to start the new release dev.
Signed-off-by: Maxime Ripard <mripard@kernel.org>
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#
ea9f8f2b |
| 05-Feb-2025 |
Jani Nikula <jani.nikula@intel.com> |
Merge drm/drm-next into drm-intel-next
Sync with v6.14-rc1.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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#
c771600c |
| 05-Feb-2025 |
Tvrtko Ursulin <tursulin@ursulin.net> |
Merge drm/drm-next into drm-intel-gt-next
We need 4ba4f1afb6a9 ("perf: Generic hotplug support for a PMU with a scope") in order to land a i915 PMU simplification and a fix. That landed in 6.12 and
Merge drm/drm-next into drm-intel-gt-next
We need 4ba4f1afb6a9 ("perf: Generic hotplug support for a PMU with a scope") in order to land a i915 PMU simplification and a fix. That landed in 6.12 and we are stuck at 6.9 so lets bump things forward.
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>
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#
7685b334 |
| 24-Jan-2025 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'perf-tools-for-v6.14-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools
Pull perf-tools updates from Namhyung Kim: "There are a lot of changes in the perf tools
Merge tag 'perf-tools-for-v6.14-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools
Pull perf-tools updates from Namhyung Kim: "There are a lot of changes in the perf tools in this cycle.
build:
- Use generic syscall table to generate syscall numbers on supported archs
- This also enables to get rid of libaudit which was used for syscall numbers
- Remove python2 support as it's deprecated for years
- Fix issues on static build with libzstd
perf record:
- Intel-PT supports "aux-action" config term to pause or resume tracing in the aux-buffer. Users can start the intel_pt event as "started-paused" and configure other events to control the Intel-PT tracing:
# perf record --kcore -e intel_pt/aux-action=start-paused/ \ -e syscalls:sys_enter_newuname/aux-action=resume/ \ -e syscalls:sys_exit_newuname/aux-action=pause/ -- uname
This requires kernel support (which was added in v6.13)
perf lock:
- 'perf lock contention' command has an ability to symbolize locks in dynamically allocated objects using slab cache name when it runs with BPF. Those dynamic locks would have "&" prefix in the name to distinguish them from ordinary (static) locks
# perf lock con -abl -E 5 sleep 1 contended total wait max wait avg wait address symbol
2 1.95 us 1.77 us 975 ns ffff9d5e852d3498 &task_struct (mutex) 1 1.18 us 1.18 us 1.18 us ffff9d5e852d3538 &task_struct (mutex) 4 1.12 us 354 ns 279 ns ffff9d5e841ca800 &kmalloc-cg-512 (mutex) 2 859 ns 617 ns 429 ns ffffffffa41c3620 delayed_uprobe_lock (mutex) 3 691 ns 388 ns 230 ns ffffffffa41c0940 pack_mutex (mutex)
This also requires kernel/BPF support (which was added in v6.13)
perf ftrace:
- 'perf ftrace latency' command gets a couple of options to support linear buckets instead of exponential. Also it's possible to specify max and min latency for the linear buckets:
# perf ftrace latency -abn -T switch_mm_irqs_off --bucket-range=100 \ --min-latency=200 --max-latency=800 -- sleep 1 # DURATION | COUNT | GRAPH | 0 - 200 ns | 186 | ### | 200 - 300 ns | 256 | ##### | 300 - 400 ns | 364 | ####### | 400 - 500 ns | 223 | #### | 500 - 600 ns | 111 | ## | 600 - 700 ns | 41 | | 700 - 800 ns | 141 | ## | 800 - ... ns | 169 | ### |
# statistics (in nsec) total time: 2162212 avg time: 967 max time: 16817 min time: 132 count: 2236
- As you can see in the above example, it nows shows the statistics at the end so that users can see the avg/max/min latencies easily
- 'perf ftrace profile' command has --graph-opts option like 'perf ftrace trace' so that it can control the tracing behaviors in the same way. For example, it can limit the function call depth or threshold
perf script:
- Improve physical memory resolution in 'mem-phys-addr' script by parsing /proc/iomem file
# perf script mem-phys-addr -- find / ... Event: mem_inst_retired.all_loads:P Memory type count percentage ---------------------------------------- ---------- ---------- 100000000-85f7fffff : System RAM 8929 69.7 547600000-54785d23f : Kernel data 1240 9.7 546a00000-5474bdfff : Kernel rodata 490 3.8 5480ce000-5485fffff : Kernel bss 121 0.9 0-fff : Reserved 3860 30.1 100000-89c01fff : System RAM 18 0.1 8a22c000-8df6efff : System RAM 5 0.0
Others:
- 'perf test' gets --runs-per-test option to run the test cases repeatedly. This would be helpful to see if it's flaky
- Add 'parse_events' method to Python perf extension module, so that users can use the same event parsing logic in the python code. One more step towards implementing perf tools in Python. :)
- Support opening tracepoint events without libtraceevent. This will be helpful if it won't use the tracing data like in 'perf stat'
- Update ARM Neoverse N2/V2 JSON events and metrics"
* tag 'perf-tools-for-v6.14-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (176 commits) perf test: Update event_groups test to use instructions perf bench: Fix undefined behavior in cmpworker() perf annotate: Prefer passing evsel to evsel->core.idx perf lock: Rename fields in lock_type_table perf lock: Add percpu-rwsem for type filter perf lock: Fix parse_lock_type which only retrieve one lock flag perf lock: Fix return code for functions in __cmd_contention perf hist: Fix width calculation in hpp__fmt() perf hist: Fix bogus profiles when filters are enabled perf hist: Deduplicate cmp/sort/collapse code perf test: Improve verbose documentation perf test: Add a runs-per-test flag perf test: Fix parallel/sequential option documentation perf test: Send list output to stdout rather than stderr perf test: Rename functions and variables for better clarity perf tools: Expose quiet/verbose variables in Makefile.perf perf config: Add a function to set one variable in .perfconfig perf test perftool_testsuite: Return correct value for skipping perf test perftool_testsuite: Add missing description perf test record+probe_libc_inet_pton: Make test resilient ...
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25768de5 |
| 21-Jan-2025 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge branch 'next' into for-linus
Prepare input updates for 6.14 merge window.
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Revision tags: v6.13-rc7, v6.13-rc6, v6.13-rc5, v6.13-rc4, v6.13-rc3, v6.13-rc2 |
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74833e37 |
| 06-Dec-2024 |
Arnaldo Carvalho de Melo <acme@redhat.com> |
perf jitdump: Fixup in_pidns member when java agent and 'perf record' are not in the same pidns
When running 'perf record' outside a container and the java agent inside a container the jit_repipe_co
perf jitdump: Fixup in_pidns member when java agent and 'perf record' are not in the same pidns
When running 'perf record' outside a container and the java agent inside a container the jit_repipe_code_load() and friends will emit PERF_RECORD_MMAP2 entries for the jitdump records and will check if we need to fixup the pid/tid:
nspid = jr->load.pid; pid = jr_entry_pid(jd, jr); tid = jr_entry_tid(jd, jr);
The jr_entry_pid() function looks if we're in the same pidns:
static pid_t jr_entry_pid(struct jit_buf_desc *jd, union jr_entry *jr) { if (jd->nsi && nsinfo__in_pidns(jd->nsi)) return nsinfo__tgid(jd->nsi); return jr->load.pid; }
But since the thread, populated from perf.data records, try to figure out if in the same pidns by actually trying, on the system where 'perf inject' is running to open a procfs file (a bug that remains to be fixed), assuming that if it is not possible that is because that thread terminated and thus we can't get its namespace info and tolerates nsinfo__init() failing, noting only that that namespace can't be entered, so don't even try.
But we can kinda get at least that info (thread->nsinfo->in_pidns) from the data in the perf.data file, namely the pid and tid in the PERF_RECORD_MMAP2 for the jit-<PID>.dump file generated from the java agent, if the PERF_RECORD_MMAP2->pid is the same as what is in the jitdump file, then we're in the same namespace, otherwise we need to use the PERF_RECORD_MMAP2->pid.
This all has to be revamped for this jitdump + running perf from outside, as the meaning of in_pidns is being abused, the initialization of nsinfo->pid with the value coming from the PERF_RECORD_MMAP2 data is wrong as it is the pid _outside_ the container since perf was running there.
The hack in this patch at least produces the expected result in this scenario by following the assumptions in the current codebase for finding maps and for generating the PERF_RECORD_MMAP2 for the ELF files synthesized from the jitdump records in jit_repipe_code_load(), etc.s
Reported-by: Francesco Nigro <fnigro@redhat.com> Reported-by: Ilan Green <igreen@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Clark Williams <williams@redhat.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: James Clark <james.clark@linaro.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yonatan Goldschmidt <yonatan.goldschmidt@granulate.io> Link: https://lore.kernel.org/r/20241206204828.507527-5-acme@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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f523347b |
| 06-Dec-2024 |
Arnaldo Carvalho de Melo <acme@redhat.com> |
perf jitdump: Accept jitdump mmaps emitted from inside containers
When the java agent is running inside a container it will emit mmaps with the format:
⬢ [acme@toolbox a]$ perf report -D | grep P
perf jitdump: Accept jitdump mmaps emitted from inside containers
When the java agent is running inside a container it will emit mmaps with the format:
⬢ [acme@toolbox a]$ perf report -D | grep PERF_RECORD_MMAP | grep \.dump 0 0x15c400 [0x90]: PERF_RECORD_MMAP2 3308868/3308868: [0x7fb8de6cb000(0x1000) @ 0 08:14 3222905945 0]: r-xp /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jit-1.dump ⬢ [acme@toolbox a]$
Since perf is running from outside the container it sees the pid 3308868 in PERF_RECORD_MMAP2, while the agent saw the pid of the profiled app inside the container, 1.
The previous validation was:
if (pid && pid2 != nsinfo__nstgid(nsi))
pid2 at this point is '1' (/jit-1.dump), so it considers this as a malformed jitdump mmap and refuses to process it.
The test ends up as:
if (3308868 && 1 != 3308868)
which is true and the jitdump is not processed.
Since 1 in the container namespace is really 3308868 in the namespace that perf is running, consider this a valid mmap.
We need to make perf realize this and behave accordingly, for now checking instead:
if (pid && pid2 && pid != nsinfo__nstgid(nsi))
Translating to:
if (3308868 && 1 && 3308868 != 3308868)
Will make the jitdump mmap to be considered valid and processed.
The jitdump is described in:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/Documentation/jitdump-specification.txt
Now we end up with the expected flurry of MMAPs, one per jitted function transformed into a little ELF file that should then be processable by the other perf features, like code annotation:
[acme@toolbox a]$ echo $JITDUMPDIR /tmp/.debug/jit [acme@toolbox a]$
First use 'perf inject':
⬢ [acme@toolbox a]$ time perf inject -i perf.data -o acme-perf-injected.data -j
Then look at the PERF_RECORD_MMAP events in the result file, that went thru the JIT map file:
⬢ [acme@toolbox a]$ ls -la /tmp/*.map -rw-r--r--. 1 acme acme 2989559 Nov 27 16:11 /tmp/perf-3308868.map [acme@toolbox a]$
It is a symbol table:
⬢ [acme@toolbox a]$ head /tmp/*.map 0x00007fb8bda5c1a0 0x00000000000000d0 java.lang.String java.lang.module.ModuleDescriptor.name() 0x00007fb8bda5c4a0 0x0000000000000178 int java.lang.StringLatin1.hashCode(byte[]) 0x00007fb8bda5c9a0 0x00000000000000d0 java.lang.String org.springframework.boot.context.config.ConfigDataLocation.getValue() 0x00007fb8bda5cca0 0x00000000000000d0 java.lang.module.ModuleDescriptor java.lang.module.ModuleReference.descriptor() 0x00007fb8bda5cfa0 0x00000000000000d0 java.lang.Object java.util.KeyValueHolder.getKey() 0x00007fb8bda5d2a0 0x00000000000000d0 java.lang.Object java.util.KeyValueHolder.getValue() 0x00007fb8bda5d5a0 0x0000000000000218 boolean jdk.internal.misc.Unsafe.compareAndSetReference(java.lang.Object, long, java.lang.Object, java.lang.Object) 0x00007fb8bda5d9a0 0x00000000000001f0 boolean jdk.internal.misc.Unsafe.compareAndSetLong(java.lang.Object, long, long, long) 0x00007fb8bda5dda0 0x00000000000001f8 void java.lang.System.arraycopy(java.lang.Object, int, java.lang.Object, int, int) 0x00007fb8bda5e1a0 0x00000000000001e8 int java.lang.Object.hashCode() ⬢ [acme@toolbox a]$
As specified in:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/Documentation/jit-interface.txt
This was collected from inside the container, so came as /tmp/perf-1.map.
To make perf, running outside the container to use it we need to copy it to /tmp/perf-3308868.map.
This is another logic that has to be added to perf to work on this scenario of running outside the container but processing things created by the hava agent running inside the container.
With all this in place we get to:
⬢ [acme@toolbox a]$ perf report -D -i acme-perf-injected.data | \ grep PERF_RECORD_MMAP > /tmp/acme-perf-injected.data.mmaps ; \ wc -l /tmp/acme-perf-injected.data.mmaps 44182 /tmp/acme-perf-injected.data.mmaps ⬢ [acme@toolbox a]$ tail /tmp/acme-perf-injected.data.mmaps 1030266786574466 0x7bc9e0 [0x98]: PERF_RECORD_MMAP2 1/78: [0x7fb8c0ceb1c0(0x8d0) @ 0x80 00:2c 238715 1]: --xs /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43989.so 1030266795288774 0x7bca78 [0x98]: PERF_RECORD_MMAP2 1/78: [0x7fb8c0cecc00(0x7e8) @ 0x80 00:2c 238716 1]: --xs /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43990.so 1030266895967339 0x7bcb10 [0x98]: PERF_RECORD_MMAP2 1/78: [0x7fb8c0cee500(0x3328) @ 0x80 00:2c 238717 1]: --xs /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43991.so 1030266915748306 0x7bcba8 [0x98]: PERF_RECORD_MMAP2 1/78: [0x7fb8c0aae0a0(0x138) @ 0x80 00:2c 238718 1]: --xs /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43992.so 1030267185851220 0x7bcc40 [0x98]: PERF_RECORD_MMAP2 1/78: [0x7fb8c0cf61e0(0x3b50) @ 0x80 00:2c 238719 1]: --xs /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43993.so 1030267231364524 0x7bccd8 [0x98]: PERF_RECORD_MMAP2 1/78: [0x7fb8c0cfea80(0x14a0) @ 0x80 00:2c 238720 1]: --xs /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43994.so 1030267425498831 0x7bcd70 [0x98]: PERF_RECORD_MMAP2 1/78: [0x7fb8c054b4a0(0x338) @ 0x80 00:2c 238721 1]: --xs /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43995.so 1030267506147888 0x7bce08 [0x98]: PERF_RECORD_MMAP2 1/78: [0x7fb8c0a995c0(0x1e8) @ 0x80 00:2c 238722 1]: --xs /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43996.so 1030268112586116 0x7bcea0 [0x98]: PERF_RECORD_MMAP2 1/78: [0x7fb8c0d02520(0x258) @ 0x80 00:2c 238723 1]: --xs /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43997.so 1030269435398150 0x7bcf38 [0x98]: PERF_RECORD_MMAP2 1/78: [0x7fb8c0d02dc0(0x278) @ 0x80 00:2c 238724 1]: --xs /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43998.so ⬢ [acme@toolbox a]$
And if we look at those tiny ELF files generated by the jitdump code used by 'perf inject' we see:
⬢ [acme@toolbox a]$ file /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43989.so /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43989.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), statically linked, BuildID[sha1]=790591db95a77d644657dfe5058658b200000000, with debug_info, not stripped ⬢ [acme@toolbox a]$ file /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43990.so /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43990.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), statically linked, BuildID[sha1]=762f932acbee53a22638bf4c2b86780200000000, with debug_info, not stripped ⬢ [acme@toolbox a]$
⬢ [acme@toolbox a]$ ls -la /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43989.so /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43990.so -rw-r--r--. 1 acme acme 9432 Nov 29 10:56 /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43989.so -rw-r--r--. 1 acme acme 7504 Nov 29 10:56 /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43990.so ⬢ [acme@toolbox a]$
And:
⬢ [acme@toolbox a]$ objdump -dS /tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43990.so | head -20
/tmp/.debug/jit/java-jit-20241126.XXTxEIOn/jitted-1-43990.so: file format elf64-x86-64
Disassembly of section .text:
0000000000000080 <Lredacted/REDACTED/REDACTED/logging/RedactedRedacted;Redacted(Lredacted/REDACTED/REDACTED/redactedRedacted/Redacted;)V>: 80: 44 8b 56 08 mov 0x8(%rsi),%r10d 84: 49 c1 e2 03 shl $0x3,%r10 88: 49 3b c2 cmp %r10,%rax 8b: 0f 85 6f 15 83 fc jne fffffffffc831600 <Lredacted/REDACTED/REDACTED/redacted/RedactedRedactedRedacted;Redacted(Lredacted/Redacted/Redacted/redactedRedacted/Redacted;)V+0xfffffffffc831580> 91: 66 66 90 data16 xchg %ax,%ax 94: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1) 9b: 00 9c: 66 66 66 90 data16 data16 xchg %ax,%ax a0: 89 84 24 00 c0 fe ff mov %eax,-0x14000(%rsp) a7: 55 push %rbp a8: 48 8b ec mov %rsp,%rbp ab: 48 83 ec 40 sub $0x40,%rsp af: 48 89 34 24 mov %rsi,(%rsp) ⬢ [acme@toolbox a]$
The thing now being investigated is why we can't annotate anything here, maybe that JITDUMPDIR is getting in the way:
⬢ [acme@toolbox a]$ perf annotate --stdio2 -i acme-perf-injected.data 'java.lang.String com.fasterxml.jackson.core.sym.CharsToNameCanonicalizer.findSymbol(char[], int, int, int)' Error: Couldn't annotate java.lang.String com.fasterxml.jackson.core.sym.CharsToNameCanonicalizer.findSymbol(char[], int, int, int): Internal error: Invalid -1 error code ⬢ [acme@toolbox a]$
In the tests I performed while merging this patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6d518ac7be6223811ab947897273b1bbef846180
It works, but then there was no JITDUMPDIR involved:
/home/acme/.debug/jit/java-jit-20241127.XXF1SRgN/jitted-3912413-4191.so
⬢ [acme@toolbox perf-tools-next]$ perf report --call-graph none --no-child -i perf-injected.data | grep jitted- | head 1.36% java jitted-3912413-54.so [.] Interpreter 0.30% C1 CompilerThre jitted-3912413-1.so [.] flush_icache_stub 0.18% java jitted-3912413-4184.so [.] org.apache.fop.fo.properties.PropertyMaker.get(int, org.apache.fop.fo.PropertyList, boolean, boolean) 0.18% java jitted-3912413-4177.so [.] org.apache.fop.layoutmgr.inline.TextLayoutManager.getNextKnuthElements(org.apache.fop.layoutmgr.LayoutContext, int) 0.13% java jitted-3912413-3845.so [.] java.text.DecimalFormat.subformatNumber(java.lang.StringBuffer, java.text.Format$FieldDelegate, boolean, boolean, int, int, int, int) 0.11% java jitted-3912413-4191.so [.] org.apache.fop.fo.FObj.addChildNode(org.apache.fop.fo.FONode) 0.09% java jitted-3912413-2418.so [.] org.apache.fop.fo.XMLWhiteSpaceHandler.handleWhiteSpace() 0.08% Reference Handl jitted-3912413-54.so [.] Interpreter 0.08% java jitted-3912413-3326.so [.] org.apache.xmlgraphics.fonts.Glyphs.stringToGlyph(java.lang.String) 0.08% java jitted-3912413-3953.so [.] org.apache.fop.layoutmgr.BreakingAlgorithm.considerLegalBreak(org.apache.fop.layoutmgr.KnuthElement, int) ⬢ [acme@toolbox perf-tools-next]$
And then:
⬢ [acme@toolbox perf-tools-next]$ perf annotate --stdio2 -i perf-injected.data 'org.apache.fop.layoutmgr.inline.TextLayoutManager.getNextKnuthElements(org.apache.fop.layoutmgr.LayoutContext, int)' | head -20 Samples: 8 of event 'cpu_atom/cycles/Pu', 4000 Hz, Event count (approx.): 8112794, [percent: local period] org.apache.fop.layoutmgr.inline.TextLayoutManager.getNextKnuthElements(org.apache.fop.layoutmgr.LayoutContext, int)() /home/acme/.debug/jit/java-jit-20241127.XXF1SRgN/jitted-3912413-4177.so Percent 0x80 <org.apache.fop.layoutmgr.inline.TextLayoutManager.getNextKnuthElements(org.apache.fop.layoutmgr.LayoutContext, int)>: nop movl 0x8(%rsi),%r10d cmpl 0x8(%rax),%r10d → jne 0 movl %eax,-0x14000(%rsp) pushq %rbp subq $0xb0,%rsp nop cmpl $0x3,0x20(%r15) ↓ jne 7037 2e: movl %ecx,0x28(%rsp) movq %rdx,%rbp movl 0x64(%rdx),%ebx cmpb $0x0,0x38(%r15) ↓ jne 3a44 movq %rsi,0x30(%rsp) 48: movq 0x30(%rsp),%r10 ⬢ [acme@toolbox perf-tools-next]$
No source code nor line numbers, that I saw in another build of perf for RHEL9, for the same workload described in the cset above (a publicly available java benchmark), so something to investigate on perf upstream running on fedora, maybe some quirk with the jdk used when building perf for RHEL 9 and for Fedora 40.
A related patch that should have make this all work is:
"perf inject jit: Add namespaces support" https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=67dec926931448d688efb5fe34f7b5a22470fc0a
But we still need to polish this some more, maybe there are differences in the agent used in NodeJS with --perf-prof and the jvmti one we're using.
Hopefully describing all the steps while we investigate this case will help us improve perf support for profiling JITed environments running in containers while profiling from inside and outside it.
Reported-by: Francesco Nigro <fnigro@redhat.com> Reported-by: Ilan Green <igreen@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Clark Williams <williams@redhat.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: James Clark <james.clark@linaro.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yonatan Goldschmidt <yonatan.goldschmidt@granulate.io> Link: https://lore.kernel.org/r/20241206204828.507527-3-acme@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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