Messages in this thread | | | Date | Fri, 13 Dec 2013 10:11:05 +0800 | From | Alex Shi <> | Subject | Re: [PATCH 2/3] x86: mm: Change tlb_flushall_shift for IvyBridge |
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On 12/13/2013 09:02 AM, Alex Shi wrote: >> > You have not replied to this concern of mine: if my concern is valid >> > then that invalidates much of the current tunings. > The benefit from pretend flush range is not unconditional, since invlpg > also cost time. And different CPU has different invlpg/flush_all > execution time.
TLB refill time is also different on different kind of cpu.
BTW, A bewitching idea is till attracting me. https://lkml.org/lkml/2012/5/23/148 Even it was sentenced to death by HPA. https://lkml.org/lkml/2012/5/24/143
That is that just flush one of thread TLB is enough for SMT/HT, seems TLB is still shared in core on Intel CPU. This benefit is unconditional, and if my memory right, Kbuild testing can improve about 1~2% in average level.
So could you like to accept some ugly quirks to do this lazy TLB flush on known working CPU? Forgive me if it's stupid.
-- Thanks Alex
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