Date: Tue, 16 Jan 2007 18:06:26 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-arch@freebsd.org Cc: Attilio Rao <attilio@freebsd.org>, Ivan Voras <ivoras@fer.hr> Subject: Re: [PATCH] Mantaining turnstile aligned to 128 bytes in i386 CPUs Message-ID: <200701161806.27245.jhb@freebsd.org> In-Reply-To: <3bbf2fe10701161454m74bd9356i3999187515c60596@mail.gmail.com> References: <3bbf2fe10607250813w8ff9e34pc505bf290e71758@mail.gmail.com> <eoji7s$cit$2@sea.gmane.org> <3bbf2fe10701161454m74bd9356i3999187515c60596@mail.gmail.com>
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On Tuesday 16 January 2007 17:54, Attilio Rao wrote: > 2007/1/16, Ivan Voras <ivoras@fer.hr>: > > Kip Macy wrote: > > > x86 pre-P4 had 32-byte cache lines. Thus older processors will not benefit. > > > > But it does seem to hurt the performance a bit - maybe it's time to add > > another CPU option like I586_CPU and I686_CPU? > > Well, it is my feeling that probabilly the align_cache parameter > should be a run-time settled parameter (in particular for ia32 CPUs > which changed a lot along the years). Yes. I think UMA_ALIGN_CACHE should be a magic cookie value and that the MD code should provide a cache line size to uma(4) during bootup, and I think you can probably just axe UMA_ALIGN_SYNC and use UMA_ALIGN_CACHE for the turnstile and sleep queue zones. -- John Baldwin
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