Date: Tue, 3 Aug 2004 13:34:40 -0700 From: Marcel Moolenaar <marcel@xcllnt.net> To: Maxime Henrion <mux@freebsd.org> Cc: cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/alpha/include cpu.h src/sys/amd64/include cpu.h src/sys/arm/include cpu.h src/sys/i386/include cpu.h src/sys/ia64/include cpu.h src/sys/powerpc/include cpu.h src/sys/sparc64/include cpu.h src/sys/kern kern_mutex.c Message-ID: <20040803203440.GA113@ns1.xcllnt.net> In-Reply-To: <20040803202342.GH13608@elvis.mu.org> References: <200408031844.i73IiRb4082245@repoman.freebsd.org> <20040803191313.GB99599@ns1.xcllnt.net> <20040803202342.GH13608@elvis.mu.org>
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On Tue, Aug 03, 2004 at 10:23:42PM +0200, Maxime Henrion wrote: > > > > Cool, but can you explain to me how exactly cpu_spinwait() is to be > > different from cpu_idle() that we cannot use cpu_idle()? > > They serve very different purposes. The cpu_spinwait() macro is used > on x86 and amd64 to insert a "pause" instruction before retrying to > obtain a spin mutex. It is supposed to improve performance on P4 and > newer machines. It is empty on other architectures because we don't > have such a thing, or at least it's not implemented. Ok, thanks. -- Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net
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