My changed had some rather significant behavioural changes to throughput.
The two issues I noticed:
* With if_start and the ifnet mbuf queue, any temporary latency
would get eaten up by some mbufs being queued. With ath_transmit()
queuing things to ath_buf's, I'd only get 512 TX buffers before I
couldn't queue any further frames.
* There's also some non-zero latency involved with TX being pushed
into a taskqueue via direct dispatch. Any time the scheduler didn't
immediately schedule the ath TX task would cause extra latency.
Various 1ge/10ge drivers implement both direct dispatch (if the TX
lock can be acquired) and deferred task transmission (if the TX lock
can't be acquired), with frames being pushed into a drbd queue.
I'll have to do this at some point, but until I figure out how to
deal with 802.11 fragments, I'll have to wait a while longer.
So what I saw:
* lots of extra latency, specially under load - if the taskqueue
wasn't immediately scheduled, things went pear shaped;
* any extra latency would result in TX ath_buf's taking their sweet time
being replenished, so any further calls to ath_transmit() would drop
mbufs.
* .. yes, there's no explicit backpressure here - things are just dropped.
Eek.
With this, the general performance has gone up, but those subtle if_start()
related race conditions are back. For some reason, this is doubly-obvious
with the AR5416 NIC and I don't quite understand why yet.
There's an unrelated issue with AR5416 performance in STA mode (it's
fine in AP mode when bridging frames, weirdly..) that requires a little
further investigation. Specifically - it works fine on a Lenovo T40
(single core CPU) running a March 2012 9-STABLE kernel, but a Lenovo T60
(dual core) running an early November 2012 kernel behaves very poorly.
The same hardware with an AR9160 or AR9280 behaves perfectly.
thread structure pointer atomically from r13 (the pcpu pointer)
for the current CPU/core.
Add a CTASSERT in machdep.c to make sure that pc_curthread is in
fact the first field in struct pcpu.
The only non-atomic operations left were those related to process-
space operations, such as casuword, subyte, suword16, fubyte,
fuword16, copyin, copyout and their variations.
The casuword function has been re-structured more complete than
the others. This way we have an example of a better bundling
without introducing a lot of risk when we get it wrong. The
other functions can be rebundled in separate commits and with
the appropriate testing.
every architecture's busdma_machdep.c. It is done by unifying the
bus_dmamap_load_buffer() routines so that they may be called from MI
code. The MD busdma is then given a chance to do any final processing
in the complete() callback.
The cam changes unify the bus_dmamap_load* handling in cam drivers.
The arm and mips implementations are updated to track virtual
addresses for sync(). Previously this was done in a type specific
way. Now it is done in a generic way by recording the list of
virtuals in the map.
Submitted by: jeff (sponsored by EMC/Isilon)
Reviewed by: kan (previous version), scottl,
mjacob (isp(4), no objections for target mode changes)
Discussed with: ian (arm changes)
Tested by: marius (sparc64), mips (jmallet), isci(4) on x86 (jharris),
amd64 (Fabian Keil <freebsd-listen@fabiankeil.de>)
since the former is defined everywhere. This cuts off some code not
necessary on non strict aligment arches.
Reviewed by: adrian
Sponsored by: Nginx, Inc.
this is not a problem as they are resolved by libgcc. The exception is for
the __aeabi_mem* functions. These call back into libc to the appropriate
function. This causes issues for static binaries as we only link against
libc once so there is no way for it to call into libgcc and back.
The fix for this is to include these symbols in libc but keep them hidden
so binaries use the libgcc version.
Fixes several problems if working with read-only pools.
Changed code originaly introduced in onnv-gate 13061:bda0decf867b
Contains changes up to illumos-gate 13700:4bc0783f6064
PR: kern/175897
Suggested by: avg
MFC after: 2 weeks
Prior to this change pinning was implemented via an ioctl (VM_SET_PINNING)
that called 'sched_bind()' on behalf of the user thread.
The ULE implementation of 'sched_bind()' bumps up 'td_pinned' which in turn
runs afoul of the assertion '(td_pinned == 0)' in userret().
Using the cpuset affinity to implement pinning of the vcpu threads works with
both 4BSD and ULE schedulers and has the happy side-effect of getting rid
of a bunch of code in vmm.ko.
Discussed with: grehan
Import vendor bugfixes regarding SA rounding, header size and layout.
This was already partially fixed by avg.
Illumos ZFS issues:
3512 rounding discrepancy in sa_find_sizes()
3513 mismatch between SA header size and layout
References:
https://www.illumos.org/issues/3512https://www.illumos.org/issues/3513
MFC after: 2 weeks
ABORT cause, since the user can also provide this kind of
information. So the receiver doesn't know who provided the
information.
While there: Fix a bug where the stack would send a malformed
ABORT chunk when using a send() call with SCTP_ABORT|SCT_SENDALL
flags.
MFC after: 3 days
Quoting the submitter:
- Added tests for SCM_BINTIME, LOCAL_PEERCRED, cmsghdr.cmsg_len
- Code that checks correctness of groups was corrected (getgroups(2) change)
- unix_cmsg.c was completely redesigned and simplified
- Use less timeout value in unix_cmsg.c for faster work
- Added support for not sending data in a message, not sending data and
data array associated with a cmsghdr structure in a message
- Existent tests were improved
- unix_cmsg.t was redesigned and simplified
Correctness of unix_cmsg verified on 7.1-STABLE, 9.1-STABLE and 10-CURRENT.
PR: bin/131567
Submitted by: Andrey Simonenko <simon@comsys.ntu-kpi.kiev.ua>
MFC after: 2 weeks
of helper functions:
- carp_master() - boolean function which is true if an address
is in the MASTER state.
- ifa_preferred() - boolean function that compares two addresses,
and is aware of CARP.
Utilize ifa_preferred() in ifa_ifwithnet().
The previous version of patch also changed source address selection
logic in jails using carp_master(), but we failed to negotiate this part
with Bjoern. May be we will approach this problem again later.
Reported & tested by: Anton Yuzhaninov <citrin citrin.ru>
Sponsored by: Nginx, Inc
With the current binutils, symbols from libheimtlm.so are loaded because
it is referenced by DT_NEEDED. This feature is not implemented in
mclinker (https://code.google.com/p/mclinker/issues/detail?id=104).
I encountered the same issue when linking with a recent devel/binutils
invoked via clang. This was the only use of DT_NEEDED in the tree so
removing it simplifies toolchain requirements.
Submitted by: Pete Chou <petechou@gmail.com> (mclinker issue)
when they're being called from the TX completion handler.
Going (back) through the taskqueue is just adding extra locking and
latency to packet operations. This improves performance a little bit
on most NICs.
It still hasn't restored the original performance of the AR5416 NIC
but the AR9160, AR9280 and later NICs behave very well with this.
Tested:
* AR5416 STA (still tops out at ~ 70mbit TCP, rather than 150mbit TCP..)
* AR9160 hostap (good for both TX and RX)
* AR9280 hostap (good for both TX and RX)
There are uncommon cases where fts_safe_changedir() may be called with a
non-NULL name that is not "..". Do not block or worse if an attacker put (a
(symlink to) a fifo or device where a directory used to be.
MFC after: 1 week
fts(3) can run (albeit more slowly and imposing the {PATH_MAX} limit) when
the current directory cannot be opened. Therefore, do not make a failure to
open the current directory (for returning to it later in -exec) fatal.
If -execdir or -delete are used, the expectation is that fts(3) will use
chdir to avoid race conditions (except for -execdir with -L). Do not break
this expectation any more than it already is by still failing if the current
directory cannot be opened.
