Alberto Donizetti [Thu, 21 Aug 2014 17:35:43 +0000 (10:35 -0700)]
time: removed from tests now obsolete assumption about Australian tz abbreviations
Australian timezones abbreviation for standard and daylight saving time were recently
changed from EST for both to AEST and AEDT in the icann tz database (see changelog
on www.iana.org/time-zones).
A test in the time package was written to check that the ParseInLocation function
understand that Feb EST and Aug EST are different time zones, even though they are
both called EST. This is no longer the case, and the Date function now returns
AEST or AEDT for australian tz on every Linux system with an up to date tz database
(and this makes the test fail).
Since I wasn't able to find another country that 1) uses daylight saving and 2) has
the same abbreviation for both on tzdata, I changed the test to make sure that
ParseInLocation does not get confused when it parses, in different locations, two
dates with the same abbreviation (this was suggested in the mailing list).
Dmitriy Vyukov [Thu, 21 Aug 2014 17:10:30 +0000 (21:10 +0400)]
runtime: remove now arg from timer callback
Cleanup before converting to Go.
Fortunately nobody using it, because it is incorrect:
monotonic runtime time instead of claimed real time.
Dmitriy Vyukov [Thu, 21 Aug 2014 08:34:26 +0000 (12:34 +0400)]
cmd/gc: fix undefined behavior
UndefinedBehaviorSanitizer claims it is UB in C:
src/cmd/gc/racewalk.c:422:37: runtime error: member access within null pointer of type 'Node' (aka 'struct Node')
src/cmd/gc/racewalk.c:423:37: runtime error: member access within null pointer of type 'Node' (aka 'struct Node')
Dmitriy Vyukov [Thu, 21 Aug 2014 07:46:53 +0000 (11:46 +0400)]
runtime: fix deadlock when gctrace
Calling ReadMemStats which does stoptheworld on m0 holding locks
was not a good idea.
Stoptheworld holding locks is a recipe for deadlocks (added check for this).
Stoptheworld on g0 may or may not work (added check for this as well).
As far as I understand scavenger will print incorrect numbers now,
as stack usage is not subtracted from heap. But it's better than deadlocking.
Brad Fitzpatrick [Wed, 20 Aug 2014 01:45:05 +0000 (18:45 -0700)]
net/http: fix TimeoutHandler data races; hold lock longer
The existing lock needed to be held longer. If a timeout occured
while writing (but after the guarded timeout check), the writes
would clobber a future connection's buffer.
Also remove a harmless warning by making Write also set the
flag that headers were sent (implicitly), so we don't try to
write headers later (a no-op + warning) on timeout after we've
started writing.
Dmitriy Vyukov [Tue, 19 Aug 2014 13:38:00 +0000 (17:38 +0400)]
runtime: make the GC bitmap a byte array
Half the code in the garbage collector accesses the bitmap
as an array of bytes instead of as an array of uintptrs.
This is tricky to do correctly in a portable fashion,
it breaks on big-endian systems.
Make the bitmap a byte array.
Simplifies markallocated, scanblock and span sweep along the way,
as we don't need to recalculate bitmap position for each word.
Dmitriy Vyukov [Tue, 19 Aug 2014 11:59:42 +0000 (15:59 +0400)]
runtime: always pass type to mallocgc when allocating scannable memory
We allocate scannable memory w/o type only in few places in runtime.
All these cases are not-performance critical (e.g. G or finq args buffer),
and in long term they all need to go away.
It's not worth it to have special code for this case in mallocgc.
So use special fake "notype" type for such allocations.
Dmitriy Vyukov [Tue, 19 Aug 2014 10:24:03 +0000 (14:24 +0400)]
runtime: allow copying of onM frame
Currently goroutines in onM can't be copied/shrunk
(including the very goroutine that triggers GC).
Special case onM to allow copying.
Dmitriy Vyukov [Tue, 19 Aug 2014 07:46:05 +0000 (11:46 +0400)]
runtime: fix memstats
Newly allocated memory is subtracted from inuse, while it was never added to inuse.
Span leftovers are subtracted from both inuse and idle,
while they were never added.
Fixes #8544.
Fixes #8430.
Russ Cox [Tue, 19 Aug 2014 01:13:11 +0000 (21:13 -0400)]
cmd/gc, runtime: refactor interface inlining decision into compiler
We need to change the interface value representation for
concurrent garbage collection, so that there is no ambiguity
about whether the data word holds a pointer or scalar.
This CL does NOT make any representation changes.
Instead, it removes representation assumptions from
various pieces of code throughout the tree.
The isdirectiface function in cmd/gc/subr.c is now
the only place that decides that policy.
The policy propagates out from there in the reflect
metadata, as a new flag in the internal kind value.
A follow-up CL will change the representation by
changing the isdirectiface function. If that CL causes
problems, it will be easy to roll back.
Update #8405.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews, r
https://golang.org/cl/129090043
Jeff R. Allen [Mon, 18 Aug 2014 21:41:28 +0000 (14:41 -0700)]
bzip2: improve performance
Improve performance of move-to-front by using cache-friendly
copies instead of doubly-linked list. Simplify so that the
underlying slice is the object. Remove the n=0 special case,
which was actually slower with the copy approach.
Dmitriy Vyukov [Mon, 18 Aug 2014 12:52:31 +0000 (16:52 +0400)]
runtime: implement transfer cache
Currently we do the following dance after sweeping a span:
1. lock mcentral
2. remove the span from a list
3. unlock mcentral
4. unmark span
5. lock mheap
6. insert the span into heap
7. unlock mheap
8. lock mcentral
9. observe empty list
10. unlock mcentral
11. lock mheap
12. grab the span
13. unlock mheap
14. mark span
15. lock mcentral
16. insert the span into empty list
17. unlock mcentral
This change short-circuits this sequence to nothing,
that is, we just cache and use the span after sweeping.
This gives us functionality similar (even better) to tcmalloc's transfer cache.
benchmark old ns/op new ns/op delta
BenchmarkMalloc8 22.2 19.5 -12.16%
BenchmarkMalloc16 31.0 26.6 -14.19%
Dmitriy Vyukov [Mon, 18 Aug 2014 12:33:39 +0000 (16:33 +0400)]
runtime: don't acquirem on malloc fast path
Mallocgc must be atomic wrt GC, but for performance reasons
don't acquirem/releasem on fast path. The code does not have
split stack checks, so it can't be preempted by GC.
Functions like roundup/add are inlined. And onM/racemalloc are nosplit.
Also add debug code that checks these assumptions.
Dmitriy Vyukov [Sat, 16 Aug 2014 05:07:55 +0000 (09:07 +0400)]
runtime: mark with non-atomic operations when GOMAXPROCS=1
Perf builders show 3-5% GC pause increase with GOMAXPROCS=1 when marking with atomic ops:
http://goperfd.appspot.com/perfdetail?commit=a8a6e765d6a87f7ccb71fd85a60eb5a821151f85&commit0=3b864e02b987171e05e2e9d0840b85b5b6476386&kind=builder&builder=linux-amd64&benchmark=http
Henning Schmiedehausen [Fri, 15 Aug 2014 22:19:02 +0000 (15:19 -0700)]
cmd/dist: goc2c ignores GOROOT_FINAL
When building golang, the environment variable GOROOT_FINAL can be set
to indicate a different installation location from the build
location. This works fine, except that the goc2c build step embeds
line numbers in the resulting c source files that refer to the build
location, no the install location.
This would not be a big deal, except that in turn the linker uses the
location of runtime/string.goc to embed the gdb script in the
resulting binary and as a net result, the debugger now complains that
the script is outside its load path (it has the install location
configured).
See https://code.google.com/p/go/issues/detail?id=8524 for the full
description.
Dmitriy Vyukov [Fri, 15 Aug 2014 18:36:12 +0000 (22:36 +0400)]
runtime: fix getgcmask
bv.data is an array of uint32s but the code was using
offsets computed for an array of bytes.
Add a test for stack GC info.
Fixes #8531.
Dmitriy Vyukov [Thu, 14 Aug 2014 17:38:24 +0000 (21:38 +0400)]
runtime: mark objects with non-atomic operations
On the go.benchmarks/garbage benchmark with GOMAXPROCS=16:
old ns/op new ns/op delta
time 13922541353170 -2.81%
cputime 2199575121373999 -2.83%
gc-pause-one 1504481213050524 -13.26%
gc-pause-total 213636 185317 -13.26%
Matthew Dempsky [Wed, 13 Aug 2014 18:16:30 +0000 (11:16 -0700)]
cmd/cgo, debug/dwarf: fix translation of zero-size arrays
In cgo, now that recursive calls to typeConv.Type() always work,
we can more robustly calculate the array sizes based on the size
of our element type.
Also, in debug/dwarf, the decision to call zeroType is made
based on a type's usage within a particular struct, but dwarf.Type
values are cached in typeCache, so the modification might affect
uses of the type in other structs. Current compilers don't appear
to share DWARF type entries for "[]foo" and "[0]foo", but they also
don't consistently share type entries in other cases. Arguably
modifying the types is an improvement in some cases, but varying
translated types according to compiler whims seems like a bad idea.
Lastly, also in debug/dwarf, zeroType only needs to rewrite the
top-level dimension, and only if the rest of the array size is
non-zero.
Dmitriy Vyukov [Wed, 13 Aug 2014 16:42:55 +0000 (20:42 +0400)]
runtime: keep objects in free lists marked as allocated.
Restore https://golang.org/cl/41040043 after GC rewrite.
Original description:
On the plus side, we don't need to change the bits on malloc and free.
On the downside, we need to mark objects in the free lists during GC.
But the free lists are small at GC time, so it should be a net win.
benchmark old ns/op new ns/op delta
BenchmarkMalloc8 21.9 20.4 -6.85%
BenchmarkMalloc16 31.1 29.6 -4.82%
Rob Pike [Wed, 13 Aug 2014 00:04:45 +0000 (17:04 -0700)]
all: copy cmd/ld/textflag.h into pkg/GOOS_GOARCH
The file is used by assembly code to define symbols like NOSPLIT.
Having it hidden inside the cmd directory makes it hard to access
outside the standard repository.
Solution: As with a couple of other files used by cgo, copy the
file into the pkg directory and add a -I argument to the assembler
to access it. Thus one can write just
#include "textflag.h"
in .s files.
The names in runtime are not updated because in the boot sequence the
file has not been copied yet when runtime is built. All other .s files
in the repository are updated.
Changes to doc/asm.html, src/cmd/dist/build.c, and src/cmd/go/build.go
are hand-made. The rest are just the renaming done by a global
substitution. (Yay sam).
Rob Pike [Tue, 12 Aug 2014 22:45:35 +0000 (15:45 -0700)]
doc/compat1.html: link to go.sys
You talked me into it. This and other links should be updated
once the new import paths for the subrepos are established.
Dmitriy Vyukov [Tue, 12 Aug 2014 21:02:01 +0000 (01:02 +0400)]
runtime/pprof: fix data race
It's unclear why we do this broken double-checked locking.
The mutex is not held for the whole duration of CPU profiling.
Fixes #8365.
This function does not have a declaration/prototype in a.h, and it is used only
in buf.c, so it is local to it and thus can be marked as private by adding
'static' to it.