Magnus Hagander <magnus@hagander.net> wrote:> On Fri, Jan 1, 2010 at 20:45, Magnus Hagander <magnus@hagander.net>
wrote:>> On Fri, Dec 4, 2009 at 11:42, Tsutomu Yamada <tsutomu@sraoss.co.jp> wrote:> >>> >> 2) use appropriate macro
anddatatypes for Windows API.> >> enables more than 32bits shared memory.> >> > Are you sure this one should use
__noop,and not __nop?> >> > __noop: http://msdn.microsoft.com/en-us/library/s6btaxcs.aspx> > __nop:
http://msdn.microsoft.com/en-us/library/aa983381.aspx>>> > I think __nop is what we want?> >> > Also, that turns it
into"nop" and not "rep nop", no?> > I did some more research, and __nop() is at least closer than> __noop(), but it's
stillnot the same.> > > > Should we perhaps instead use __yield, per:> >
http://msdn.microsoft.com/en-us/library/2b2h26kx.aspx>> On further reading, __yield() is only available on Itanium.
This spinlock code was came from below.
http://archives.postgresql.org/pgsql-hackers/2008-07/msg00307.php
Sorry, I didn't care which macro was better.
I found 'YieldProcessor' in MSDN.
http://msdn.microsoft.com/en-us/library/ms687419%28VS.85%29.aspx
YieldProcessor was defined in "winnt.h".
The definition changes depending on architecture and compiler version.
__asm { rep nop };
__mm_pause();
__yield();
YieldProcessor become "__mm_pause()" in _AMD64_.
So "__mm_pause()" is better?
// test program
#include <windows.h>
main()
{ YieldProcessor();
}
// end
// cl /E test.c > out.i
// tail out.i
// # I recommend redirecting to file, The output become large.
Tsutomu Yamada
SRA OSS, Inc. Japan