net80211 / LinuxKPI: 802.11: revert / redo enum ieee80211_sta_rx_bw

The initial thought of migrating the LinuxKPI 802.11 enum into net80211
for shared use did not work out well. Currently in the ne

net80211 / LinuxKPI: 802.11: revert / redo enum ieee80211_sta_rx_bw

The initial thought of migrating the LinuxKPI 802.11 enum into net80211
for shared use did not work out well. Currently in the need for yet
another adjustment, I decided to undo/de-couple net80211 and
LinuxKPI 802.11 again.

The enum name now gets used in LinuxKPI based wifi drivers and it
turns out it is spelt differntly than what I used initially.
This creates a conflict.

net80211 still in the need to be able to express BW_320 in an uint8_t
will likely be fine with the current solution as well. Rename the
enum and prefixes in net80211 to "net80211" instead of "ieee80211".
Apart from the names/prefix we leave the values the same.

In LinuxKPI add the enum with the expected name and use it there
throughout to make modern versions of LinuxKPI based wifi drivers
compile.

Sponsored by: The FreeBSD Foundation
Fixes: ca389486a9599, 2c8b0d6205f6f
MFC after: 3 days
Reviewed by: adrian
Differential Revision: https://reviews.freebsd.org/D52064

show more ...

ath: fix 20MHz HT short-gi logic.

This was broken in an earlier commit

(ca389486a9599768e0ba69dca13c208020623083).

PR: kern/285096
Differential Revision: https://reviews.freebsd.org/D49196
Fixes:

ath: fix 20MHz HT short-gi logic.

This was broken in an earlier commit

(ca389486a9599768e0ba69dca13c208020623083).

PR: kern/285096
Differential Revision: https://reviews.freebsd.org/D49196
Fixes: ca389486a9599768e0ba69dca13c208020623083
Reviewed by: bz

show more ...

net80211 / LinuxKPI 802.11: use enum ieee80211_sta_rx_bw for ni_chw

net80211 node ni_chw currently encodes the channel width as Mhz number.
LinuxKPI 802.11 uses enum ieee80211_sta_rx_bw for the same

net80211 / LinuxKPI 802.11: use enum ieee80211_sta_rx_bw for ni_chw

net80211 node ni_chw currently encodes the channel width as Mhz number.
LinuxKPI 802.11 uses enum ieee80211_sta_rx_bw for the same.

Rather than keeping the "20" and "40" throughout the code (eventually
expanded to 80/160/320) switch them over to use the enum throughout
and add a print mask for debug output. While designed as bitmask it
is not supposed to be used as such; the bitmask is only used to be
able to use %b with a print mask.

Once we get to 320Mhz channel widths we would otherwise also need to
extend the uint8_t in struct ieee80211_node; making
enum ieee80211_sta_rx_bw __packed allows us for three more channel
widths without breaking the KBI (if we were not to use %b with a
print_mask but use a lookup function for the string we could extend
it for a long time).

Sponsored by: The FreeBSD Foundation
MFC after: 14 days
Reviewed by: adrian
Differential Revision: https://reviews.freebsd.org/D47891

show more ...

ath: use the new net80211 methods for AMPDU density/limit, short-GI

Now that net80211 has this code, just leverage it instead of rolling
our own.

Differential Revision: https://reviews.freebsd.org/

ath: use the new net80211 methods for AMPDU density/limit, short-GI

Now that net80211 has this code, just leverage it instead of rolling
our own.

Differential Revision: https://reviews.freebsd.org/D47748

Reviewed by: bz

show more ...

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

show more ...

ath(4): Fix a sysctl description and a typo in a comment

- s/delimeter/delimiter/

MFC after: 7 days

Provide MS() and SM() macros for 80211 and wireless drivers.

We have (two versions) of MS() and SM() macros which we use throughout
the wireless code. Change all but three places (ath_hal, rtwn, an

Provide MS() and SM() macros for 80211 and wireless drivers.

We have (two versions) of MS() and SM() macros which we use throughout
the wireless code. Change all but three places (ath_hal, rtwn, and rsu)
to the newly provided _IEEE80211_MASKSHIFT() and _IEEE80211_SHIFTMASK()
macros. Also change one internal case using both _S and _M instead of
just _S away from _M (one of the reasons rtwn and rsu were not changed).

This was done semi-mechanically. No functional changes intended.

Requested by: gnn (D26091)
Reviewed by: adrian (pre line wrap)
MFC after: 2 weeks
Sponsored by: Rubicon Communications, LLC (d/b/a "Netgate")
Differential Revision: https://reviews.freebsd.org/D26539

show more ...

ath: clean up empty lines in .c and .h files

[ath] [ath_rate] Extend ath_rate_sample to better handle 11n rates and aggregates.

My initial rate control code was .. suboptimal. I wanted to at least get MCS
rates sent, but it didn't do anywhere

[ath] [ath_rate] Extend ath_rate_sample to better handle 11n rates and aggregates.

My initial rate control code was .. suboptimal. I wanted to at least get MCS
rates sent, but it didn't do anywhere near enough to handle low signal level links
or remotely keep accurate statistics.

So, 8 years later, here's what I should've done back then.

* Firstly, I wasn't at all tracking packet sizes other than the two buckets
(250 and 1600 bytes.) So, extend it to include 4096, 8192, 16384, 32768 and
65536. I may go add 2048 at some point if I find it's useful.

This is important for a few reasons. First, when forming A-MPDU or AMSDU
aggregates the frame sizes are larger, and thus the TX time calculation
is woefully, increasingly wrong. Secondly, the behaviour of 802.11 channels
isn't some fixed thing, both due to channel conditions and radios themselves.
Notably, there was some observations done a few years ago on 11n chipsets
which noticed longer aggregates showed an increase in failed A-MPDU sub-frame
reception as you got further along in the transmit time. It could be due to
a variety of things - transmitter linearity, channel conditions changing,
frequency/phase drift, etc - but the observation was to potentially form
shorter aggregates to improve BER.

* .. and then modify the ath TX path to report the length of the aggregate sent,
so as the statistics kept would line up with the correct bucket.

* Then on the rate control look-up side - i was also only using the first frame
length for an A-MPDU rate control lookup which isn't good enough here.
So, add a new method that walks the TID software queue for that node to
find out what the likely length of data available is. It isn't ALL of the
data in the queue because we'll only ever send enough data to fit inside the
block-ack window, so limit how many bytes we return to roughly what ath_tx_form_aggr()
would do.

* .. and cache that in the first ath_buf in the aggregate so it and the eventual
AMPDU length can be returned to the rate control code.

* THEN, modify the rate control code to look at them both when deciding which bucket
to attribute the sent frame on. I'm erring on the side of caution and using the
size bucket that the lookup is based on.

Ok, so now the rate lookups and statistics are "more correct". However, MCS rates
are not the same as 11abg rates in that they're not a monotonically incrementing
set of faster rates and you can't assume that just because a given MCS rate fails,
the next higher one wouldn't work better or be a lower average tx time.

So, I had to do a bunch of surgery to the best rate and sample rate math.
This is the bit that's a WIP.

* First, simplify the statistics updates (update_stats()) to do a single pass on
all rates.
* Next, make sure that each rate average tx time is updated based on /its/ failure/success.
Eg if you sent a frame with { MCS15, MCS12, MCS8 } and MCS8 succeeded, MCS15 and MCS
12 would have their average tx time updated for /their/ part of the transmission,
not the whole transmission.
* Next, EWMA wasn't being fully calculated based on the /failures/ in each of the
rate attempts. So, if MCS15, MCS12 failed above but MCS8 didn't, then ensure
that the statistics noted that /all/ subframes failed at those rates, rather than
the eventual set of transmitted/sent frames. This ensures the EWMA /and/ average
TX time are updated correctly.
* When picking a sample rate and initial rate, probe rates aroud the current MCS
but limit it to MCS0..7 /for all spatial streams/, rather than doing crazy things
like hitting MCS7 and then probing MCS8 - MCS8 is basically MCS0 but two spatial
streams. It's a /lot/ slower than MCS7. Also, the reverse is true - if we're at
MCS8 then don't probe MCS7 as part of it, it's not likely to succeed.
* Fix bugs in pick_best_rate() where I was /immediately/ choosing the highest MCS
rate if there weren't any frames yet transmitted. I was defaulting to 25% EWMA and
.. then each comparison would accept the higher rate. Just skip those; sampling
will fill in the details.

So, this seems to work a lot better. It's not perfect; I'm still seeing a lot of
instability around higher MCS rates because there are bursts of loss/retransmissions
that aren't /too/ bad. But i'll keep iterating over this and tidying up my hacks.

Ok, so why this still something I'm poking at? rather than porting minstrel_ht?

ath_rate_sample tries to minimise airtime, not maximise throughput. I have
extended it with an EWMA based on sub-frame success/failures - high MCS rates
that have partially successful receptions still show super short average frame
times, but a /lot/ of retransmits have to happen for that to work.
So for MCS rates I also track this EWMA and ensure that the rates I'm choosing
don't have super crappy packet failures. I don't mind not getting lower
peak throughput versus minstrel_ht; instead I want to see if I can make "minimise
airtime" work well.

Tested:

* AR9380, STA mode
* AR9344, STA mode
* AR9580, STA/AP mode

show more ...

net80211 / LinuxKPI: 802.11: revert / redo enum ieee80211_sta_rx_bw

The initial thought of migrating the LinuxKPI 802.11 enum into net80211
for shared use did not work out well. Currently in the ne

net80211 / LinuxKPI: 802.11: revert / redo enum ieee80211_sta_rx_bw

The initial thought of migrating the LinuxKPI 802.11 enum into net80211
for shared use did not work out well. Currently in the need for yet
another adjustment, I decided to undo/de-couple net80211 and
LinuxKPI 802.11 again.

The enum name now gets used in LinuxKPI based wifi drivers and it
turns out it is spelt differntly than what I used initially.
This creates a conflict.

net80211 still in the need to be able to express BW_320 in an uint8_t
will likely be fine with the current solution as well. Rename the
enum and prefixes in net80211 to "net80211" instead of "ieee80211".
Apart from the names/prefix we leave the values the same.

In LinuxKPI add the enum with the expected name and use it there
throughout to make modern versions of LinuxKPI based wifi drivers
compile.

Sponsored by: The FreeBSD Foundation
Fixes: ca389486a9599, 2c8b0d6205f6f
MFC after: 3 days
Reviewed by: adrian
Differential Revision: https://reviews.freebsd.org/D52064

show more ...

ath: fix 20MHz HT short-gi logic.

This was broken in an earlier commit

(ca389486a9599768e0ba69dca13c208020623083).

PR: kern/285096
Differential Revision: https://reviews.freebsd.org/D49196
Fixes:

ath: fix 20MHz HT short-gi logic.

This was broken in an earlier commit

(ca389486a9599768e0ba69dca13c208020623083).

PR: kern/285096
Differential Revision: https://reviews.freebsd.org/D49196
Fixes: ca389486a9599768e0ba69dca13c208020623083
Reviewed by: bz

show more ...

net80211 / LinuxKPI 802.11: use enum ieee80211_sta_rx_bw for ni_chw

net80211 node ni_chw currently encodes the channel width as Mhz number.
LinuxKPI 802.11 uses enum ieee80211_sta_rx_bw for the same

net80211 / LinuxKPI 802.11: use enum ieee80211_sta_rx_bw for ni_chw

net80211 node ni_chw currently encodes the channel width as Mhz number.
LinuxKPI 802.11 uses enum ieee80211_sta_rx_bw for the same.

Rather than keeping the "20" and "40" throughout the code (eventually
expanded to 80/160/320) switch them over to use the enum throughout
and add a print mask for debug output. While designed as bitmask it
is not supposed to be used as such; the bitmask is only used to be
able to use %b with a print mask.

Once we get to 320Mhz channel widths we would otherwise also need to
extend the uint8_t in struct ieee80211_node; making
enum ieee80211_sta_rx_bw __packed allows us for three more channel
widths without breaking the KBI (if we were not to use %b with a
print_mask but use a lookup function for the string we could extend
it for a long time).

Sponsored by: The FreeBSD Foundation
MFC after: 14 days
Reviewed by: adrian
Differential Revision: https://reviews.freebsd.org/D47891

show more ...

ath: use the new net80211 methods for AMPDU density/limit, short-GI

Now that net80211 has this code, just leverage it instead of rolling
our own.

Differential Revision: https://reviews.freebsd.org/

ath: use the new net80211 methods for AMPDU density/limit, short-GI

Now that net80211 has this code, just leverage it instead of rolling
our own.

Differential Revision: https://reviews.freebsd.org/D47748

Reviewed by: bz

show more ...

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

show more ...

ath(4): Fix a sysctl description and a typo in a comment

- s/delimeter/delimiter/

MFC after: 7 days

Provide MS() and SM() macros for 80211 and wireless drivers.

We have (two versions) of MS() and SM() macros which we use throughout
the wireless code. Change all but three places (ath_hal, rtwn, an

Provide MS() and SM() macros for 80211 and wireless drivers.

We have (two versions) of MS() and SM() macros which we use throughout
the wireless code. Change all but three places (ath_hal, rtwn, and rsu)
to the newly provided _IEEE80211_MASKSHIFT() and _IEEE80211_SHIFTMASK()
macros. Also change one internal case using both _S and _M instead of
just _S away from _M (one of the reasons rtwn and rsu were not changed).

This was done semi-mechanically. No functional changes intended.

Requested by: gnn (D26091)
Reviewed by: adrian (pre line wrap)
MFC after: 2 weeks
Sponsored by: Rubicon Communications, LLC (d/b/a "Netgate")
Differential Revision: https://reviews.freebsd.org/D26539

show more ...

ath: clean up empty lines in .c and .h files

[ath] [ath_rate] Extend ath_rate_sample to better handle 11n rates and aggregates.

My initial rate control code was .. suboptimal. I wanted to at least get MCS
rates sent, but it didn't do anywhere

[ath] [ath_rate] Extend ath_rate_sample to better handle 11n rates and aggregates.

My initial rate control code was .. suboptimal. I wanted to at least get MCS
rates sent, but it didn't do anywhere near enough to handle low signal level links
or remotely keep accurate statistics.

So, 8 years later, here's what I should've done back then.

* Firstly, I wasn't at all tracking packet sizes other than the two buckets
(250 and 1600 bytes.) So, extend it to include 4096, 8192, 16384, 32768 and
65536. I may go add 2048 at some point if I find it's useful.

This is important for a few reasons. First, when forming A-MPDU or AMSDU
aggregates the frame sizes are larger, and thus the TX time calculation
is woefully, increasingly wrong. Secondly, the behaviour of 802.11 channels
isn't some fixed thing, both due to channel conditions and radios themselves.
Notably, there was some observations done a few years ago on 11n chipsets
which noticed longer aggregates showed an increase in failed A-MPDU sub-frame
reception as you got further along in the transmit time. It could be due to
a variety of things - transmitter linearity, channel conditions changing,
frequency/phase drift, etc - but the observation was to potentially form
shorter aggregates to improve BER.

* .. and then modify the ath TX path to report the length of the aggregate sent,
so as the statistics kept would line up with the correct bucket.

* Then on the rate control look-up side - i was also only using the first frame
length for an A-MPDU rate control lookup which isn't good enough here.
So, add a new method that walks the TID software queue for that node to
find out what the likely length of data available is. It isn't ALL of the
data in the queue because we'll only ever send enough data to fit inside the
block-ack window, so limit how many bytes we return to roughly what ath_tx_form_aggr()
would do.

* .. and cache that in the first ath_buf in the aggregate so it and the eventual
AMPDU length can be returned to the rate control code.

* THEN, modify the rate control code to look at them both when deciding which bucket
to attribute the sent frame on. I'm erring on the side of caution and using the
size bucket that the lookup is based on.

Ok, so now the rate lookups and statistics are "more correct". However, MCS rates
are not the same as 11abg rates in that they're not a monotonically incrementing
set of faster rates and you can't assume that just because a given MCS rate fails,
the next higher one wouldn't work better or be a lower average tx time.

So, I had to do a bunch of surgery to the best rate and sample rate math.
This is the bit that's a WIP.

* First, simplify the statistics updates (update_stats()) to do a single pass on
all rates.
* Next, make sure that each rate average tx time is updated based on /its/ failure/success.
Eg if you sent a frame with { MCS15, MCS12, MCS8 } and MCS8 succeeded, MCS15 and MCS
12 would have their average tx time updated for /their/ part of the transmission,
not the whole transmission.
* Next, EWMA wasn't being fully calculated based on the /failures/ in each of the
rate attempts. So, if MCS15, MCS12 failed above but MCS8 didn't, then ensure
that the statistics noted that /all/ subframes failed at those rates, rather than
the eventual set of transmitted/sent frames. This ensures the EWMA /and/ average
TX time are updated correctly.
* When picking a sample rate and initial rate, probe rates aroud the current MCS
but limit it to MCS0..7 /for all spatial streams/, rather than doing crazy things
like hitting MCS7 and then probing MCS8 - MCS8 is basically MCS0 but two spatial
streams. It's a /lot/ slower than MCS7. Also, the reverse is true - if we're at
MCS8 then don't probe MCS7 as part of it, it's not likely to succeed.
* Fix bugs in pick_best_rate() where I was /immediately/ choosing the highest MCS
rate if there weren't any frames yet transmitted. I was defaulting to 25% EWMA and
.. then each comparison would accept the higher rate. Just skip those; sampling
will fill in the details.

So, this seems to work a lot better. It's not perfect; I'm still seeing a lot of
instability around higher MCS rates because there are bursts of loss/retransmissions
that aren't /too/ bad. But i'll keep iterating over this and tidying up my hacks.

Ok, so why this still something I'm poking at? rather than porting minstrel_ht?

ath_rate_sample tries to minimise airtime, not maximise throughput. I have
extended it with an EWMA based on sub-frame success/failures - high MCS rates
that have partially successful receptions still show super short average frame
times, but a /lot/ of retransmits have to happen for that to work.
So for MCS rates I also track this EWMA and ensure that the rates I'm choosing
don't have super crappy packet failures. I don't mind not getting lower
peak throughput versus minstrel_ht; instead I want to see if I can make "minimise
airtime" work well.

Tested:

* AR9380, STA mode
* AR9344, STA mode
* AR9580, STA/AP mode

show more ...

sys/dev: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error

sys/dev: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

show more ...

MFhead@r313243

Merge ^/head r312309 through r312623.

[ath] only apply the AR9300 delimiter workaround for the first sub-frame.

This is supposed to only be applied to the first subframe and only if
RTS/CTS is being done. I'm still not yet checking RTS

[ath] only apply the AR9300 delimiter workaround for the first sub-frame.

This is supposed to only be applied to the first subframe and only if
RTS/CTS is being done. I'm still not yet checking RTS/CTS exchange status
so it's just happening for all subframes on AR9380 and later.

This gets MCS23 throughput up from around 250mbit to 303mbit with RTS/CTS
protection enabled, and around 330mbit with no HT protection enabled.

Now, MCS23 has a PHY rate of 450mbit and we should be seeing closer to
400mbit for a straight one-way UDP test, but this beats the previous
maximum throughput.

Tested:

* AR9380 (STA) -> AR9580 (AP) - STA with the modifications, doing UDP TX
test using iperf.

show more ...

[ath] improve the debugging when looking into the maximum A-MPDU size being chosen.

This is how I caught the "why are we only sending 8K aggregates?" problem.