Date: Fri, 16 Jul 2010 15:14:29 +0400 From: pluknet <pluknet@gmail.com> To: Jung-uk Kim <jkim@freebsd.org> Cc: Oliver Fromme <olli@lurza.secnetix.de>, freebsd-stable@freebsd.org, Andriy Gapon <avg@icyb.net.ua> Subject: Re: 8.1-PRERELEASE: CPU packages not detected correctly Message-ID: <AANLkTimtSNncnDDh5gk0RbYKe0yghtiVG6Ka7v4b1Gzn@mail.gmail.com> In-Reply-To: <201007151518.17012.jkim@FreeBSD.org> References: <201007151657.o6FGv97V080710@lurza.secnetix.de> <4C3F4BBB.30606@icyb.net.ua> <201007151507.33998.jkim@FreeBSD.org> <201007151518.17012.jkim@FreeBSD.org>
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On 15 July 2010 23:18, Jung-uk Kim <jkim@freebsd.org> wrote: > On Thursday 15 July 2010 03:07 pm, Jung-uk Kim wrote: >> On Thursday 15 July 2010 01:56 pm, Andriy Gapon wrote: >> > on 15/07/2010 19:57 Oliver Fromme said the following: >> > > In topo_probe(), cpu_high is 0xd, so topo_probe_0xb() is >> > > called. =A0But the cpuid 0xb instruction doesn't seem to >> > > return useful data: =A0All values are zero already in the >> > > first level, so cpu_cores remains 0. >> > > >> > > Back in topo_probe(), there is a fallback if cpu_cores is >> > > stil 0: =A0It assigns mp_ncpu to cpu_cores, so it gets 8 >> > > which is wrong. >> > > >> > > I patched topo_probe() so it calls topo_probe_0x4() after >> > > topo_probe_0xb() if cpu_cores is still 0. =A0I think this >> > > is a better fallback procedure. =A0With this patch, cpu_cores >> > > gets the value 4 which is the correct one, finally: >> > > >> > > FreeBSD/SMP: Multiprocessor System Detected: 8 CPUs >> > > FreeBSD/SMP: 2 package(s) x 4 core(s) >> > >> > Thank you for debugging this issue! >> > Not sure if this is the best patch that there can be, but its >> > direction is definitely correct. >> > As the Intel document says (translated to our x86 mp_machdep.c >> > terms): if cpu_high >=3D 0xb then we should execute >> > cpuid_count(0xb, 0, p) and examine EBX value (p[1]), only if it's >> > non-zero should we proceed with topo_probe_0xb(), otherwise we >> > should fall back to topo_probe_0x4, etc. >> > >> > I think that your addition achieves this effect, perhaps just not >> > as explicitly as I would preferred. >> > >> > Jung-uk, what do you think? >> >> Yes, you're right. =A0Please try new patch: >> >> http://people.freebsd.org/~jkim/mp_machdep2.diff > > I uploaded the patch again, it's compile-tested this now. > Just tried with the patch against 8.1-rc2. 2x E5520 - OK, no changes FreeBSD/SMP: Multiprocessor System Detected: 16 CPUs FreeBSD/SMP: 2 package(s) x 4 core(s) x 2 SMT threads 2x E5440 - now OK FreeBSD/SMP: Multiprocessor System Detected: 8 CPUs FreeBSD/SMP: 2 package(s) x 4 core(s) 1x 5050 - OK, no changes FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs FreeBSD/SMP: 1 package(s) x 2 core(s) x 2 HTT threads --=20 wbr, pluknet
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