Date: Thu, 2 Feb 2012 08:46:47 +0800 From: Paul Ambrose <ambrosehua@gmail.com> To: Konstantin Belousov <kostikbel@gmail.com> Cc: freebsd-current <freebsd-current@freebsd.org> Subject: Re: Does anyone try kib's Sandy Bridge PCID patch (pcid.2.patch)? Message-ID: <CAMwoQQ5QeWA_za3QgQH5wPfuFNpOXmNY0nmEqMfSuU4AuYx3_A@mail.gmail.com> In-Reply-To: <20120131152828.GF3283@deviant.kiev.zoral.com.ua> References: <CAMwoQQ4onrPWO1FBuDtW6nPsoaxNPP4wevv0DEJ4CorzEKb5JA@mail.gmail.com> <20120130063607.GV2726@deviant.kiev.zoral.com.ua> <CAMwoQQ4fP%2BV5VngOGLUDG5D9Di2Y5HBHSBzGq%2BODGkEsaAffpg@mail.gmail.com> <20120130164316.GW2726@deviant.kiev.zoral.com.ua> <CAMwoQQ7Obe%2BmFBYiSqZ66NV1j6MaLCjkHA5hjHAV%2BPah4Mg3ZQ@mail.gmail.com> <20120131152828.GF3283@deviant.kiev.zoral.com.ua>
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=D4=DA 2012=C4=EA1=D4=C231=C8=D5 =CF=C2=CE=E711:28=A3=ACKonstantin Belousov= <kostikbel@gmail.com> =D0=B4=B5=C0=A3=BA > On Tue, Jan 31, 2012 at 09:23:50AM +0800, Paul Ambrose wrote: >> ?? 2012??1??31?? ????12:43??Kostik Belousov <kostikbel@gmail.com> ?????? >> > On Mon, Jan 30, 2012 at 07:08:13PM +0800, Paul Ambrose wrote: >> >> ?? 2012??1??30?? ????2:36??Kostik Belousov <kostikbel@gmail.com> ????= ?? >> >> > On Mon, Jan 30, 2012 at 10:15:51AM +0800, Paul Ambrose wrote: >> >> >> I have two boxes, one is AMD Athlon 610e 2.4G with FreeBSD-curren= t >> >> >> patched with pcid.2.patch? It works well without other issue and i= t >> >> >> seem the pcid patch >> >> >> does not affect other part of the kernel. The other one is Sandy >> >> > Athlons do not have PCID and probably will never implement it. They= use >> >> > other tricks to get similar optimizations, transparently to the OS. >> >> > >> >> Just curious, is this AMD similar optimizations >> >> Address Space Number (ASN) and Global flag >> >> US Patent 6,604,187. >> >> http://www.chip-architect.com/news/2003_09_21_Detailed_Architecture_o= f_AMDs_64bit_Core.html >> > This and the same-important next item 'The TLB Flush Filter' is what >> > I referred to. >> > >> >> I did not found anything about ASN in the AMD manual >> > It is a transparent optimization, which does not require any OS suppor= t. >> > Intel PCID is completely different, it shall be explicitely handled by= OS. >> > It is some consequence of the nested pages support, AFAIU. >> > >> >> >> >> >> Bridge i5-2300 with FreeBSD 9 release patched with pcid.1.patch( t= he >> >> >> pcid.2.patch seems >> >> >> dependent on AVX and XSAVE stuffs which is available on -current).= But >> >> >> it hangs up just in a few minutes. I doubt the nvidia-driver which= is >> >> >> not recompiled with >> >> >> patched kernel is the root, I will check this out later, but does >> >> >> anyone meet similar problem? >> >> > There are two many variations compared to the config I did tested. >> >> > I do not see anything obvious in the changes between HEAD and stabl= e/9 >> >> > which could be blamed. Nvidia driver might be bigger suspect, but a= gain, >> >> > I am not aware of anything wrong with it. >> >> > >> >> >> >> >> >> I have two question about the pcid.2.patch >> >> > >> >> > Item 2 is clean, I fixed it. >> >> > >> >> > For the item 1, I was only able to decipher the proposal to optimiz= e >> >> > the global shootdown handler to restore the %cr3 with bit 64 set to= not >> >> > invalidate current PCID. Is there some more changes ? >> >> > >> >> yes, that is what I meant. I was wondering using another way that eac= h >> >> process has different >> >> pcid in each active processor, just as the freebsd mips and powerpc >> >> uses. But obviously this way >> >> is more friendly to non-pcid x86 processor. >> > Each vmspace (or pmap) has unique PCID with the patch, at least until >> > PCID space (12bit) is not exhausted. To really exhaust it, you need 40= 95 >> > processes, so it is unlikely but possible event with the current setti= ngs. >> > >> Thank you for your explanation. I just disabled nvidia-driver( not >> load it) , and >> use "buildworld buildkernel" to test the pcid.1.patch with 9-release, >> it seems the box reset before >> completing the buildkernel, the attachment is my kernel config, would >> you mind try it on >> 9-release with pcid.1.patch? I will git 10-current a try to see if >> there is something wrong with my hardware > > I just did checkout + buildworld + buildkernel with -j 10 on UFS with > PCID turned on, everything finished fine. It is up to date HEAD. > > sandy% sysctl vm.stats.sys.v_swtch vm.pmap.pcid_save_cnt > vm.stats.sys.v_swtch: 13743519 > vm.pmap.pcid_save_cnt: 7853519 > I.e. the TLB was not flushed one each second context switch. > > Trying the HEAD with the patch is probably easiest way forward. Unfortunately, I try 10-current(HEAD) with pcid.3.patch in my i5-2300 box, system panic
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