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  1. 02 Oct, 2015 10 commits
    • Austin Clements's avatar
      runtime: scan objects with finalizers concurrently · 608c1b0d
      Austin Clements authored 
      This reduces pause time by ~25% relative to tip and by ~50% relative
to Go 1.5.1.

Currently one of the steps of STW mark termination is to loop (in
parallel) over all spans to find objects with finalizers in order to
mark all objects reachable from these objects and to treat the
finalizer special as a root. Unfortunately, even if there are no
finalizers at all, this loop takes roughly 1 ms/heap GB/core, so
multi-gigabyte heaps can quickly push our STW time past 10ms.

Fix this by moving this scan from mark termination to concurrent scan,
where it can run in parallel with mutators. The loop itself could also
be optimized, but this cost is small compared to concurrent marking.

Making this scan concurrent introduces two complications:

1) The scan currently walks the specials list of each span without
locking it, which is safe only with the world stopped. We fix this by
speculatively checking if a span has any specials (the vast majority
won't) and then locking the specials list only if there are specials
to check.

2) An object can have a finalizer set after concurrent scan, in which
case it won't have been marked appropriately by concurrent scan. If
the finalizer is a closure and is only reachable from the special, it
could be swept before it is run. Likewise, if the object is not marked
yet when the finalizer is set and then becomes unreachable before it
is marked, other objects reachable only from it may be swept before
the finalizer function is run. We fix this issue by making
addfinalizer ensure the same marking invariants as markroot does.

For multi-gigabyte heaps, this reduces max pause time by 20%–30%
relative to tip (depending on GOMAXPROCS) and by ~50% relative to Go
1.5.1 (where this loop was neither concurrent nor parallel). Here are
the results for the garbage benchmark:

               ---------------- max pause ----------------
Heap   Procs   Concurrent scan   STW parallel scan   1.5.1
24GB     12         18ms              23ms            37ms
24GB      4         18ms              25ms            37ms
 4GB      4         3.8ms            4.9ms           6.9ms

In all cases, 95%ile pause time is similar to the max pause time. This
also improves mean STW time by 10%–30%.

Fixes #11485.

Change-Id: I9359d8c3d120a51d23d924b52bf853a1299b1dfd
Reviewed-on: https://go-review.googlesource.com/14982Reviewed-by: default avatarRick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
      608c1b0d
    • Austin Clements's avatar
      runtime: introduce gcMode type for GC modes · fbd2660a
      Austin Clements authored 
      Currently, the GC modes constants are untyped and functions pass them
around as ints. Clean this up by introducing a proper type for these
constant.

Change-Id: Ibc022447bdfa203644921fbb548312d7e2272e8d
Reviewed-on: https://go-review.googlesource.com/14981Reviewed-by: default avatarBrad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
      fbd2660a
    • Austin Clements's avatar
      runtime: fix out-of-date comment on gcWork usage · 1b84bb8c
      Austin Clements authored 
      Change-Id: I3c21ffa80a5c14911e07238b1f64bec686ed7b72
Reviewed-on: https://go-review.googlesource.com/14980Reviewed-by: default avatarMinux Ma <minux@golang.org>
      1b84bb8c
    • Brad Fitzpatrick's avatar
      syscall: skip a couple tests when running under Kubernetes · f35310ed
      Brad Fitzpatrick authored 
      Update #12815

Change-Id: I3bf6de74bc8ab07000fe9a4308299839ef20632f
Reviewed-on: https://go-review.googlesource.com/15283Reviewed-by: default avatarEvan Brown <evanbrown@google.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: default avatarIan Lance Taylor <iant@golang.org>
      f35310ed
    • Robert Griesemer's avatar
      readme: emphasize issue tracker is for bugs/proposals · 4c2a4004
      Robert Griesemer authored 
      Removed direct link to issue tracker in the README - it makes it too
easy to use it for a question - and it's abused multiple times a day
for questions. It's easy enough to find it if there's a real issue
to report.

Added sentence to point people at golang-nuts and the new forum.

Change-Id: If75bab888cda064aceeefc49ef672fbb964f8f54
Reviewed-on: https://go-review.googlesource.com/15284Reviewed-by: default avatarJason Buberel <jbuberel@google.com>
Reviewed-by: default avatarBrad Fitzpatrick <bradfitz@golang.org>
      4c2a4004
    • Ian Gudger's avatar
      database/sql: fix case where Stmt.Close discards error · 73fe6123
      Ian Gudger authored 
      Fixes a case where the Stmt.Close() function in database/sql discards any error generated by the Close() function of the contained driverStmt.

Fixes #12798

Change-Id: I40384d6165856665b062d15a643e4ecc09d63fda
Reviewed-on: https://go-review.googlesource.com/15178Reviewed-by: default avatarBrad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
      73fe6123
    • Ian Lance Taylor's avatar
      misc/cgo/testsanitizers: skip test for version of clang before 3.6 · f80ff56a
      Ian Lance Taylor authored 
      I've tested with clang 3.6.  The builder is running 3.5, and fails.

Fixes #12814.

Change-Id: I087fb75c3a24bed7f7fa5e9d7a1444590a316d63
Reviewed-on: https://go-review.googlesource.com/15259Reviewed-by: default avatarBrad Fitzpatrick <bradfitz@golang.org>
      f80ff56a
    • David Crawshaw's avatar
      runtime: darwin/386 entrypoint for c-archive · 47ccf96a
      David Crawshaw authored 
      Change-Id: Ic22597b5e2824cffe9598cb9b506af3426c285fd
Reviewed-on: https://go-review.googlesource.com/12412
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarIan Lance Taylor <iant@golang.org>
      47ccf96a
    • Michael Hudson-Doyle's avatar
      runtime: adjust the ppc64x memmove and memclr to copy by word as much as it can · 2c911143
      Michael Hudson-Doyle authored 
      Issue #12552 can happen on ppc64 too, although much less frequently in my
testing. I'm fairly sure this fixes it (2 out of 200 runs of oracle.test failed
without this change and 0 of 200 failed with it). It's also a lot faster for
large moves/clears:

name           old speed      new speed       delta
Memmove1-6      157MB/s ± 9%    144MB/s ± 0%    -8.20%         (p=0.004 n=10+9)
Memmove2-6      281MB/s ± 1%    249MB/s ± 1%   -11.53%        (p=0.000 n=10+10)
Memmove3-6      376MB/s ± 1%    328MB/s ± 1%   -12.64%        (p=0.000 n=10+10)
Memmove4-6      475MB/s ± 4%    345MB/s ± 1%   -27.28%         (p=0.000 n=10+8)
Memmove5-6      540MB/s ± 1%    393MB/s ± 0%   -27.21%        (p=0.000 n=10+10)
Memmove6-6      609MB/s ± 0%    423MB/s ± 0%   -30.56%         (p=0.000 n=9+10)
Memmove7-6      659MB/s ± 0%    468MB/s ± 0%   -28.99%         (p=0.000 n=8+10)
Memmove8-6      705MB/s ± 0%   1295MB/s ± 1%   +83.73%          (p=0.000 n=9+9)
Memmove9-6      740MB/s ± 1%   1241MB/s ± 1%   +67.61%         (p=0.000 n=10+8)
Memmove10-6     780MB/s ± 0%   1162MB/s ± 1%   +48.95%         (p=0.000 n=10+9)
Memmove11-6     811MB/s ± 0%   1180MB/s ± 0%   +45.58%          (p=0.000 n=8+9)
Memmove12-6     820MB/s ± 1%   1073MB/s ± 1%   +30.83%         (p=0.000 n=10+9)
Memmove13-6     849MB/s ± 0%   1068MB/s ± 1%   +25.87%        (p=0.000 n=10+10)
Memmove14-6     877MB/s ± 0%    911MB/s ± 0%    +3.83%        (p=0.000 n=10+10)
Memmove15-6     893MB/s ± 0%    922MB/s ± 0%    +3.25%         (p=0.000 n=10+9)
Memmove16-6     897MB/s ± 1%   2418MB/s ± 1%  +169.67%         (p=0.000 n=10+9)
Memmove32-6     908MB/s ± 0%   3927MB/s ± 2%  +332.64%         (p=0.000 n=10+8)
Memmove64-6    1.11GB/s ± 0%   5.59GB/s ± 0%  +404.64%          (p=0.000 n=9+9)
Memmove128-6   1.25GB/s ± 0%   6.71GB/s ± 2%  +437.49%         (p=0.000 n=9+10)
Memmove256-6   1.33GB/s ± 0%   7.25GB/s ± 1%  +445.06%        (p=0.000 n=10+10)
Memmove512-6   1.38GB/s ± 0%   8.87GB/s ± 0%  +544.43%        (p=0.000 n=10+10)
Memmove1024-6  1.40GB/s ± 0%  10.00GB/s ± 0%  +613.80%        (p=0.000 n=10+10)
Memmove2048-6  1.41GB/s ± 0%  10.65GB/s ± 0%  +652.95%         (p=0.000 n=9+10)
Memmove4096-6  1.42GB/s ± 0%  11.01GB/s ± 0%  +675.37%         (p=0.000 n=8+10)
Memclr5-6       269MB/s ± 1%    264MB/s ± 0%    -1.80%        (p=0.000 n=10+10)
Memclr16-6      600MB/s ± 0%    887MB/s ± 1%   +47.83%        (p=0.000 n=10+10)
Memclr64-6     1.06GB/s ± 0%   2.91GB/s ± 1%  +174.58%         (p=0.000 n=8+10)
Memclr256-6    1.32GB/s ± 0%   6.58GB/s ± 0%  +399.86%         (p=0.000 n=9+10)
Memclr4096-6   1.42GB/s ± 0%  10.90GB/s ± 0%  +668.03%         (p=0.000 n=8+10)
Memclr65536-6  1.43GB/s ± 0%  11.37GB/s ± 0%  +697.83%          (p=0.000 n=9+8)
GoMemclr5-6     359MB/s ± 0%    360MB/s ± 0%    +0.46%        (p=0.000 n=10+10)
GoMemclr16-6    750MB/s ± 0%   1264MB/s ± 1%   +68.45%        (p=0.000 n=10+10)
GoMemclr64-6   1.17GB/s ± 0%   3.78GB/s ± 1%  +223.58%         (p=0.000 n=10+9)
GoMemclr256-6  1.35GB/s ± 0%   7.47GB/s ± 0%  +452.44%        (p=0.000 n=10+10)

Update #12552

Change-Id: I7192e9deb9684a843aed37f58a16a4e29970e893
Reviewed-on: https://go-review.googlesource.com/14840Reviewed-by: default avatarMinux Ma <minux@golang.org>
      2c911143
    • Mikio Hara's avatar
      runtime: drop sigfwd from signal forwarding unsupported platforms · 9fb79380
      Mikio Hara authored 
      This change splits signal_unix.go into signal_unix.go and
signal2_unix.go and removes the fake symbol sigfwd from signal
forwarding unsupported platforms for clarification purpose.

Change-Id: I205eab5cf1930fda8a68659b35cfa9f3a0e67ca6
Reviewed-on: https://go-review.googlesource.com/12062Reviewed-by: default avatarIan Lance Taylor <iant@golang.org>
      9fb79380
  3. 01 Oct, 2015 9 commits
  5. 30 Sep, 2015 10 commits
  7. 29 Sep, 2015 9 commits
  9. 28 Sep, 2015 2 commits
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