Re: [patch] fix i386 mutex fastpath on FRAME_POINTER && !DEBUG_MUTEXES

[Chuck Ebbert]

In-Reply-To: <Pine.LNX.4.58.0601110511590.24014@xxxxxxxxxxxxxxxxxxxxxxxx>

On Wed, 11 Jan 2006, Ingo Molnar wrote:

> On Wed, 11 Jan 2006, Chuck Ebbert wrote:
>
> > 
> >                 LOCK    "   decl (%%eax)        \n"                     \
> >                         "   jns 1f              \n"                     \
> >                         "   call "#fail_fn"     \n"                     \
> >                         "1:                     \n"                     \
> >                                                                         \
> >                 :"=a" (dummy)                                           \
> >                 : "a" (count)                                           \
> > 
> > 
> > Will the extra taken forward conditional jump in the fastpath cause much
> > of a slowdown?
> 
> yeah - the fastpath is much more common than the slowpath.

But that's how the spinlock code does it.  Should that be changed to put the
spinloops in .text.lock and make the fastpaths a fall-through?

-- 
Chuck
Currently reading: _Olympos_ by Dan Simmons
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