Introduces two-phase goroutine parking mechanism -- prepare to park, commit park.
This mechanism does not require backing mutex to protect wait predicate.
Use it in netpoll. See comment in netpoll.goc for details.
This slightly reduces contention between reader, writer and read/write io notifications;
and just eliminates a bunch of mutex operations from hotpaths, thus making then faster.
benchmark old ns/op new ns/op delta
BenchmarkTCP4ConcurrentReadWrite 2109 1945 -7.78%
BenchmarkTCP4ConcurrentReadWrite-2 1162 1113 -4.22%
BenchmarkTCP4ConcurrentReadWrite-4 798 755 -5.39%
BenchmarkTCP4ConcurrentReadWrite-8 803 748 -6.85%
BenchmarkTCP4Persistent 9411 9240 -1.82%
BenchmarkTCP4Persistent-2 5888 5813 -1.27%
BenchmarkTCP4Persistent-4 4016 3968 -1.20%
BenchmarkTCP4Persistent-8 3943 3857 -2.18%
R=golang-codereviews, mikioh.mikioh, gobot, iant, rsc
CC=golang-codereviews, khr
https://golang.org/cl/45700043
Currently lots of sys allocations are not accounted in any of XxxSys,
including GC bitmap, spans table, GC roots blocks, GC finalizer blocks,
iface table, netpoll descriptors and more. Up to ~20% can unaccounted.
This change introduces 2 new stats: GCSys and OtherSys for GC metadata
and all other misc allocations, respectively.
Also ensures that all XxxSys indeed sum up to Sys. All sys memory allocation
functions require the stat for accounting, so that it's impossible to miss something.
Also fix updating of mcache_sys/inuse, they were not updated after deallocation.
test/bench/garbage/parser before:
Sys 670064344
HeapSys 610271232
StackSys 65536
MSpanSys 14204928
MCacheSys 16384
BuckHashSys 1439992
after:
Sys 670064344
HeapSys 610271232
StackSys 65536
MSpanSys 14188544
MCacheSys 16384
BuckHashSys 3194304
GCSys 39198688
OtherSys 3129656
Fixes#5799.
R=rsc, dave, alex.brainman
CC=golang-dev
https://golang.org/cl/12946043
Go runtime support for dragonfly/amd64, largely based of the existing
FreeBSD runtime (with some clues from the varialus/godfly work).
R=bradfitz
CC=golang-dev
https://golang.org/cl/13088044
I've placed net.runtime_Semacquire into netpoll.goc,
but netbsd does not yet use netpoll.goc.
R=golang-dev, bradfitz, iant
CC=golang-dev
https://golang.org/cl/12699045
The mutex, fdMutex, handles locking and lifetime of sysfd,
and serializes Read and Write methods.
This allows to strip 2 sync.Mutex.Lock calls,
2 sync.Mutex.Unlock calls, 1 defer and some amount
of misc overhead from every network operation.
On linux/amd64, Intel E5-2690:
benchmark old ns/op new ns/op delta
BenchmarkTCP4Persistent 9595 9454 -1.47%
BenchmarkTCP4Persistent-2 8978 8772 -2.29%
BenchmarkTCP4ConcurrentReadWrite 4900 4625 -5.61%
BenchmarkTCP4ConcurrentReadWrite-2 2603 2500 -3.96%
In general it strips 70-500 ns from every network operation depending
on processor model. On my relatively new E5-2690 it accounts to ~5%
of network op cost.
Fixes#6074.
R=golang-dev, bradfitz, alex.brainman, iant, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/12418043
GetQueuedCompletionStatusEx allows to dequeue a batch of completion
notifications, which is more efficient than dequeueing one by one.
benchmark old ns/op new ns/op delta
BenchmarkClientServerParallel4 100605 90945 -9.60%
BenchmarkClientServerParallel4-2 90225 74504 -17.42%
R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/12436044
Currently Darwin and FreeBSD support and NetBSD and OpenBSD do not
support EV_RECEIPT flag. We will drop use of EV_RECEIPT for now.
Also enables to build runtime-integrated network pollster on
freebsd/amd64,386 and openbsd/amd64,386. It just does build but never
runs pollster stuff.
This is in preparation for runtime-integrated network pollster for BSD
variants.
Update #5199
R=dvyukov, minux.ma
CC=golang-dev
https://golang.org/cl/11759044
- change runtime_pollWait so it does not return
closed or timeout if IO is ready - windows must
know if IO has completed or not even after
interruption;
- add (*pollDesc).Prepare(mode int) that can be
used for both read and write, same for Wait;
- introduce runtime_pollWaitCanceled and expose
it in net as (*pollDesc).WaitCanceled(mode int);
Full windows netpoll changes are
here https://golang.org/cl/8670044/.
R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/10485043
Fixes#5061.
Current code relies on the fact that fd's are automatically removed from epoll set when closed. However, it is not true. Underlying file description is removed from epoll set only when *all* fd's referring to it are closed.
There are 2 bad consequences:
1. Kernel delivers notifications on already closed fd's.
2. The following sequence of events leads to error:
- add fd1 to epoll
- dup fd1 = fd2
- close fd1 (not removed from epoll since we've dup'ed the fd)
- dup fd2 = fd1 (get the same fd as fd1)
- add fd1 to epoll = EEXIST
So, if fd can be potentially dup'ed of fork'ed, it's necessary to explicitly remove the fd from epoll set.
R=golang-dev, bradfitz, dave
CC=golang-dev
https://golang.org/cl/7870043
