Date: Tue, 10 Mar 2015 09:02:08 -0700 From: Freddie Cash <fjwcash@gmail.com> To: "Pokala, Ravi" <rpokala@panasas.com> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>, "lokadamus@gmx.de" <lokadamus@gmx.de>, Rui Paulo <rpaulo@me.com> Subject: Re: detecting hyperthreading Message-ID: <CAOjFWZ594OKAZ95ybegKiu%2BKr4-YeEZfJGVmv1obhxeZjVVbNA@mail.gmail.com> In-Reply-To: <D1246191.12F7D6%rpokala@panasas.com> References: <D12358C5.12F652%rpokala@panasas.com> <9F2E1411-B517-4BC8-AF61-BB15EE35083C@me.com> <D123957A.12F6CA%rpokala@panasas.com> <54FF1343.1020705@gmx.de> <D1246191.12F7D6%rpokala@panasas.com>
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On Tue, Mar 10, 2015 at 8:56 AM, Pokala, Ravi <rpokala@panasas.com> wrote: > -----Original Message----- > From: "lokadamus@gmx.de" <lokadamus@gmx.de> > Date: 2015-03-10, Tuesday at 08:52 > To: Ravi Pokala <rpokala@panasas.com>, Rui Paulo <rpaulo@me.com> > Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org> > Subject: Re: detecting hyperthreading > > >Have you look at dmesg? > >My system is a P4 with HTT. > >dmesg |more > [...] > >CPU: Intel(R) Pentium(R) 4 CPU 3.00GHz (3000.00-MHz 686-class CPU) > > Origin = "GenuineIntel" Id = 0xf29 Family = 0xf Model = 0x2 > >Stepping = 9 > > > >Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,M > >CA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> > > Features2=0x4400<CNXT-ID,xTPR> > > Of course. :-) > > But there are two problems: > > (1) That just tells me HTT is supported by the CPU, not that if kernel is > using it. > (2) It's difficult to parse. > > Of the two, (1) is the bigger concern for my use-case. > 6 lines or so below the Features line shows the kernel loading "cpu0 (BSP)", and then "cpu1 (AP/HT)". Compare that to a system without HTT, where any extra cpus only show "(AP)". It's not perfect, but one could grep through /var/run/dmesg.boot looking for "cpu" lines and checking for "(AP)" or "(AP/HT)". -- Freddie Cash fjwcash@gmail.com
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