Russ Cox [Fri, 25 Mar 2011 17:47:07 +0000 (13:47 -0400)]
runtime/pprof: disable test on darwin
Fixes #1641.
Actually it side steps the real issue, which is that the
setitimer(2) implementation on OS X is not useful for
profiling of multi-threaded programs. I filed the below
using the Apple Bug Reporter.
This program creates a new pthread that loops, wasting cpu time.
In the main pthread, it sleeps on a condition that will never come true.
Before doing so it sets up an interval timer using ITIMER_PROF.
The handler prints a message saying which thread it is running on.
POSIX does not specify which thread should receive the signal, but
in order to be useful in a user-mode self-profiler like pprof or gprof
http://code.google.com/p/google-perftools
http://www.delorie.com/gnu/docs/binutils/gprof_25.html
it is important that the thread that receives the signal is the one
whose execution caused the timer to expire.
Linux and FreeBSD handle this by sending the signal to the process's
queue but delivering it to the current thread if possible:
http://lxr.linux.no/linux+v2.6.38/kernel/signal.c#L802
807 /*
808 * Now find a thread we can wake up to take the signal off the queue.
809 *
810 * If the main thread wants the signal, it gets first crack.
811 * Probably the least surprising to the average bear.
812 * /
http://fxr.watson.org/fxr/source/kern/kern_sig.c?v=FREEBSD8;im=bigexcerpts#L1907
1914 /*
1915 * Check if current thread can handle the signal without
1916 * switching context to another thread.
1917 * /
On those operating systems, this program prints:
$ ./a.out
signal on cpu-chewing looper thread
signal on cpu-chewing looper thread
signal on cpu-chewing looper thread
signal on cpu-chewing looper thread
signal on cpu-chewing looper thread
signal on cpu-chewing looper thread
signal on cpu-chewing looper thread
signal on cpu-chewing looper thread
signal on cpu-chewing looper thread
signal on cpu-chewing looper thread
$
The OS X kernel does not have any such preference. Its get_signalthread
does not prefer current_thread(), in contrast to the other two systems,
so the signal gets delivered to the first thread in the list that is able to
handle it, which ends up being the main thread in this experiment.
http://fxr.watson.org/fxr/source/bsd/kern/kern_sig.c?v=xnu-1456.1.26;im=excerpts#L1666
$ ./a.out
signal on sleeping main thread
signal on sleeping main thread
signal on sleeping main thread
signal on sleeping main thread
signal on sleeping main thread
signal on sleeping main thread
signal on sleeping main thread
signal on sleeping main thread
signal on sleeping main thread
signal on sleeping main thread
$
The fix is to make get_signalthread use the same heuristic as
Linux and FreeBSD, namely to use current_thread() if possible
before scanning the process thread list.
Ian Lance Taylor [Fri, 25 Mar 2011 17:36:46 +0000 (10:36 -0700)]
test: match gccgo error messages for label.go and label1.go.
label.go:30:1: error: label ‘L6’ already defined
label.go:28:1: note: previous definition of ‘L6’ was here
label.go:23:1: error: label ‘L4’ defined and not used
label.go:52:2: error: label ‘defalt’ defined and not used
label.go:17:1: error: label ‘L2’ defined and not used
label.go:26:1: error: label ‘L5’ defined and not used
label.go:20:1: error: label ‘L3’ defined and not used
label.go:14:1: error: label ‘L1’ defined and not used
Robert Griesemer [Thu, 24 Mar 2011 18:45:52 +0000 (11:45 -0700)]
go/parser: resolve identifiers properly
Correctly distinguish between lhs and rhs identifiers
and resolve/declare them accordingly.
Collect field and method names in respective scopes
(will be available after some minor AST API changes).
Also collect imports since it's useful to have that
list directly w/o having to re-traverse the AST
(will also be available after some minor AST API changes).
Sameer Ajmani [Thu, 24 Mar 2011 14:35:39 +0000 (10:35 -0400)]
misc/emacs: gofmt: don't clobber the current buffer on failure
Change M-x gofmt to display errors in a new buffer instead of
clobbering the current buffer.
Add gofmt-before-save, which runs gofmt when in go-mode. This
can be used with before-save-hook. Add to your .emacs:
(add-hook 'before-save-hook 'gofmt-before-save)
Alex Brainman [Thu, 24 Mar 2011 00:20:28 +0000 (11:20 +1100)]
syscall: StartProcess fixes for windows
- StartProcess will work with relative (to attr.Dir, not
current directory) executable filenames
- StartProcess will only work if executable filename points
to the real file, it will not search for executable in the
$PATH list and others (see CreateProcess manual for details)
- StartProcess argv strings can contain any characters
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4306041
Gustavo Niemeyer [Mon, 21 Mar 2011 03:07:22 +0000 (00:07 -0300)]
rpc: increase server_test timeout
These timeouts are breaking tests in very slow
systems every once in a while. I've noticed
problems when compiling the Ubuntu packages for
arm, specifically.
Rob Pike [Fri, 18 Mar 2011 18:54:36 +0000 (11:54 -0700)]
rpc: keep free lists of Request and Response structures.
Also in the common case avoid unnecessary buffering in
the channel.
Removes 13 allocations per round trip. Now at 86, down from
144 a week ago.
Robert Griesemer [Thu, 17 Mar 2011 22:32:29 +0000 (15:32 -0700)]
go/parser: fix memory leak by making a copy of token literals
The scanner returns slices into the original source
for token values. If those slices are making it into
the AST and from there into other long-living data
structures (e.g. godoc search), references to the
original source are kept around involuntarily.
For the current godoc and source tree, this change reduces
memory consumption after indexing and before GC by ~92MB
or almost 30%, and by ~10MB after GC (or about 6%).
Ian Lance Taylor [Thu, 17 Mar 2011 20:42:40 +0000 (13:42 -0700)]
net: Don't force epoll/kqueue to wake up in order to add new events.
In conjunction with the non-blocking system call CL, this
gives about an 8% performance improvement on a client/server
test running on my local machine.
Rob Pike [Thu, 17 Mar 2011 17:47:42 +0000 (10:47 -0700)]
gob: eliminate two more allocations in decode.
- just an oversight; we were reallocating a buffer.
- use unsafe to avoid allocating storage for a string twice.
Rob Pike [Thu, 17 Mar 2011 01:03:13 +0000 (18:03 -0700)]
gob: remove a few more allocations.
- use enc.err and dec.err instead of return values in deferred error catcher
- replace io.WriteString with buffer.WriteString
now at:
mallocs per encode of type Bench: 7
mallocs per decode of type Bench: 8
Rob Pike [Wed, 16 Mar 2011 17:32:21 +0000 (10:32 -0700)]
testing: compile regexp only once
The -test.run and -test.bench flags were compilng the regexp for ever test
function, which was mucking up memory profiles. Add a simple wrapper
to save the compiled state so that the regexp is compiled only once for
each flag.
Robert Griesemer [Wed, 16 Mar 2011 00:45:16 +0000 (17:45 -0700)]
go/printer: output tuning for gofix
If braces don't have position information for a composite
literal, don't assume alignment of key:value pairs under
the (wrong) assumption that there may be multiple lines.