Date: Mon, 14 Jan 2008 09:18:45 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-current@freebsd.org Cc: Joe Marcus Clarke <marcus@freebsd.org>, current <current@freebsd.org> Subject: Re: RFC: Adding a hw.features[2] sysctl Message-ID: <200801140918.45895.jhb@freebsd.org> In-Reply-To: <1200197787.67286.13.camel@shumai.marcuscom.com> References: <1200197787.67286.13.camel@shumai.marcuscom.com>
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On Saturday 12 January 2008 11:16:27 pm Joe Marcus Clarke wrote: > I find it would be useful to have the list of CPU features available via > a sysctl. Currently, he only ways to get this information are to have > linprocfs mounted, or parse dmesg.boot (if it exists). Attached are > patches to add hw.features and hw.features2 sysctls for i386 and amd64 > (where a list of CPU features is applicable). The results are identical > to the Features and Features2 strings from dmesg: > > hw.features2: 0x41d<SSE3,RSVD2,MON,DS_CPL,CNXT-ID> > hw.features: > 0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> > > Comments? I would put this under machdep. rather than hw. since it is x86-specific. I also think having feature and feature2 might be a bit odd as you have to query two different nodes. Someday there might be a features3 when features2 runs out of bits and then all the apps would have to be updated again perhaps. Maybe something like: machdep.cpufeature.FPU=1 machdep.cpufeature.VME=1 Or maybe if you use named nodes like this you could do dev.cpu.X.FPU=1, dev.cpu.X.VME=1, etc. (possibly dev.cpu.X.feature.FPU=1, etc.) -- John Baldwin
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