Worker threads now use a pthread_cond_t to wait for work instead of
burning the cpu up.
Obtained from: DragonflyBSD (07774aea0ccf64a48fcfad8899e3bf7c8f18277a)
MFC after: 2 weeks
* limit cabq to 64 - in practice if this stays at ath_txbuf then
all buffers can be tied up by a very busy broadcast domain (eg ARP
storm, way too much MDNS/NETBIOS). It's been like this in the
freebsd-wifi-build AP project for the longest time.
* Now that I figured out the hilarity inherent in aggregate forming
and AR9380 EDMA work, change the per-node to 64 frames by default.
I'll do some more work to shorten the queue latency introduced when
doing data so TCP isn't so terrible, but it's now no longer /always/
tens of milliseconds of extra latency when doing active iperf tests.
Notes:
The reason for the extra latency is partly tx/rx taskqueue handling and
scheduling, and partly due to a lack of airtime/QoS awareness of per-node
traffic. Ideally we'd have different limits/priorities on the QoS/TID
levels per node so say, voice/video data got a better share of buffer
allocations over best effort/bulk data, but we currently don't implement
that. It's not /hard/ to do, I just need to do it.
Tested:
* AR9380 (STA), AR9580 (hostap) - both with the relevant changes.
TCP is now at around 180mbit with rate control and RTS protection
enabled. UDP stays at 355mbit at MCS23, no HT protection.
This is two fixes, which establishes what I /think/ is pretty close to the
theoretical PHY maximum speed on the AR9380 devices.
* When doing A-MPDU on a TID, don't queue to the hardware directly if
the hardware queue is busy. This gives us time to get more packets
queued up (and the hardware is busy, so there's no point in queuing
more to the hardware right now) to potentially form an A-MPDU.
This fixes up the throughput issue I was seeing where a couple hundred
single frames were being sent a second interspersed between A-MPDU
frames. It just happened that the software queue had exactly one
frame in it at that point. Queuing it until the hardware finishes
transmitting isn't exactly costly.
* When determining whether to dequeue from a software node/TID queue into
the hardware queue, fix up the checks to work right for EDMA chips
(ar9380 and later.) Before it was not dispatching anything until
the FIFO was empty. Now we allow it to dispatch another aggregate
up to the hardware aggregate limit, like I intended with the earlier
work.
This allows a 5GHz HT40, short-GI, "htprotmode off" test at MCS23
to achieve 357 Mbit/sec in a one-way UDP test. The stars have to be
aligned /just right/ so there are no retries but it can happen.
Just don't expect it to work in an OTA test if your 2yo is running
around the room - MCS23 is very very sensitive to channel conditions.
Tested:
* AR9380 STA (test) -> AR9580 hostap
TODO:
* More thorough testing on pre-AR9380 chips (AR5416, AR9160, AR9280)
* (Finally) teach ath_rate_sample about throughput/latency rather than
air time, so I can get good transmit rates with a 2yo running around.
When investigating performance on UDP TX on the AR9380 I found that the
following sequence was occuring:
* INTR
* EINPROGRESS - nothing yet
* INTR
* TXSTATUS - process a TX completion for an aggregate
* INTR, INTR
* TXSTATUS - process a TX completion for an aggregate
* TXD, TXD ... populate frames from the hardware queue and submit
What should be happening is a completed TXSTATUS fires off more packets
that are queued on active TIDs.
What /was/ happening was after that first TXSTATUS the TX queue hardware queue
was still empty, so it didn't push anything into the FIFO. Only after the
second TXSTATUS did any progress get made.
This is one of two commits - it ensures that the software TX queue scheduler
is called /after/ TX completion, otherwise no frames from the software staging
queues will be processed into the hardware queues.
The second commit will fix it so it populates aggregate frames correctly
when the above occurs - right now ath_txq_sched() is called, but it doesn't
populate anything because its pre-check conditions are wrong.
Whilst here, add/tweak debugging.
Tested:
* AR9380 STA (testing device) -> AR9580 hostap
Building kernel with devel/powerpc64-gcc (6.2.0) yields the following error:
/usr/src/sys/powerpc/powerpc/db_trace.c:299:20: error: calling
'__builtin_frame_address' with a nonzero argument is unsafe
[-Werror=frame-address]
Work around this by dereferencing the frame address manually instead.
PR: 215600
Reported by: Mark Millard <markmi AT dsl-only DOT net>
MFC after: 2 weeks
This ioctl has been considered legacy by upstream since the DTrace code
was first imported, and is unused. The removal also allows some
simplification of dtrace_helper_slurp().
Also remove a bogus copyout in the DTRACEHIOC_ADDDOF handler. Due to a
bug, it would overwrite an in-memory copy of the DOF header rather than
the passed-in DOF helper. Moreover, DTRACEHIOC_ADDDOF already copies the
helper back out automatically since its argument has the IOC_OUT attribute.
critical_exit().
Based on the discussion with: jhb
Reviewed by: imp
Sponsored by: The FreeBSD Foundation
Differential revision: D9276
MFC after: 1 week
overwrites an existing file rather than removing it and creating a
new file. If the old and new version of the file both have extended
attributes and the extended attributes of the two versions of the
file are different, the result is that the new file ends up with
the union of the extended attributes of the old and new files.
To get the behavior of replacing the extended attributes rather
than augmenting them requires explicitly removing the old attributes
and then adding the new ones.
To get this behavior, the old file must be unlinked (which clears
out the old extended attributes). Then the new file of the same
name must be created and the new extended attributes added to it.
This behavior can be obtained by specifying the -u flag when running
restore. Rather than defaulting the -u option to on and possibly
breaking existing scripts using restore, this change simply notes
in the restore.8 manual page that the -u flag is recommended when
using restore on filesystems that contain extended attributes.
PR: 216127
Reported by: dewayne at heuristicsystems.com.au
Differential Revision: https://reviews.freebsd.org/D9208
The delta here is just between the current TX/RX copmletion and the previous
TX/RX completion. The metadata needed to link TX descriptor timestamps to their
/completion/ timestamp isn't there yet.
Our base binutils sets -many by default anyway, but external gcc may not do
this.
PR: kern/215948
Submitted by: Mark Millard <markmi AT dsl-only DOT net>
Reported by: Mark Millard
MFC after: 2 weeks
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.
mappings for armv6 pmap zero and copy operations to the MD PCPU region.
Change sysmap initialization to only allocate KVA pages for CPUs that
are actually present.
While here, collapse CMAP3 into CMAP2 (their use was mutually exclusive
anyway) and "recover" some space in PCPU padding that has always been
available due to 64-byte cacheline padding.
Reviewed by: skra
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D9172
descriptor state will not change anymore). This seems to eliminate the
race where we can miss a stalled queue under high load.
While here remove the unnecessary curly brackets.
Reported by: Konstantin Kormashev <konstantin@netgate.com>
MFC after: 3 days
Sponsored by: Rubicon Communications, LLC (Netgate)
Set both IEEE80211_HTCAP_LDPC and IEEE80211_HTC_TXLDPC capability flags
if LDPC is supported + set 'do_ldpc = 1' only when it is not disabled,
not just supported.
Reviewed by: adrian
Differential Revision: https://reviews.freebsd.org/D9277
- Pad small packets to 60 bytes and not 64 (exclude the CRC bytes);
- Pad the packet using m_append(9), if the packet has enough space for
padding, which is usually true, it will not be necessary append a newly
allocated mbuf to the chain.
Suggested by: yongari
MFC after: 3 days
Sponsored by: Rubicon Communications, LLC (Netgate)
It is only a first step and not perfect, but better then nothing.
The main blocker is CAM target frontend, that can not be unloaded,
since CAM does not have mechanism to unregister periph driver now.
MFC after: 2 weeks
Stop testing for LK_RETRY and error multiple times. Also postpone the
VI_DOOMED until after LK_RETRY was seen as it reads from the vnode.
No functional changes.
