Date: Thu, 22 Sep 2005 15:04:38 -0400 From: Jung-uk Kim <jkim@FreeBSD.org> To: freebsd-current@FreeBSD.org Cc: Colin Percival <cperciva@FreeBSD.org> Subject: Re: [PATCH] AMD multicore detection Message-ID: <200509221504.44919.jkim@FreeBSD.org> In-Reply-To: <43325364.8090208@freebsd.org> References: <200509211550.27524.jkim@FreeBSD.org> <43325114.4090907@gneto.com> <43325364.8090208@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thursday 22 September 2005 02:47 am, Colin Percival wrote: > Martin Nilsson wrote: > > Jung-uk Kim wrote: > >> New patch is here: > >> http://people.freebsd.org/~jkim/multicore.diff > >> > >> Please test and let me know. I don't have multicore CPU to test > >> it for myself. :-( > > > > The below is on a Pentium D 820 (Dualcore). I don't like that the > > two cores are reported as hyperthreading when the CPU does not > > support hyperthreading (only the 840 EE does). If we ship 6.0 > > with HT disabled I'm afraid that it will turn off one of the > > cores, right? > > It shouldn't. Dual-core processors claim to be hyperthreaded, but > when I wrote the patch which disabled hyperthreading I added extra > (and rather complicated) code to detect dual-core processors and > *not* disable them. > > If I got it wrong, please let me know. :-) I think what's happening is this: /* * If the deterministic cache parameters are not * available, or if no caches were reported to exist, * just accept what the HTT flag indicated. */ if (hyperthreading_cpus == 0) hyperthreading_cpus = logical_cpus; I googled a bit and found this: http://crystalmark.info/BBS/c-board.cgi?cmd=one;no=726;id=report It's japanese but you will be able to read the report. ;-) cpuid with %eax = 4 doesn't seem to return anything. Jung-uk Kim > Colin Percival
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200509221504.44919.jkim>