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Date: Thu, 03 May 2012 17:15:19 +0800 From: Alex Shi <alex.shi@...el.com> To: Borislav Petkov <bp@...64.org> CC: andi.kleen@...el.com, tim.c.chen@...ux.intel.com, jeremy@...p.org, chrisw@...s-sol.org, akataria@...are.com, tglx@...utronix.de, mingo@...hat.com, hpa@...or.com, rostedt@...dmis.org, fweisbec@...il.com, riel@...hat.com, luto@....edu, avi@...hat.com, len.brown@...el.com, paul.gortmaker@...driver.com, dhowells@...hat.com, fenghua.yu@...el.com, yinghai@...nel.org, cpw@....com, steiner@....com, linux-kernel@...r.kernel.org, yongjie.ren@...el.com Subject: Re: [PATCH 2/3] x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_range On 05/02/2012 09:44 PM, Borislav Petkov wrote: > On Wed, May 02, 2012 at 07:38:47PM +0800, Alex Shi wrote: >>> Are you saying you want to have this setting per family? >> >> Set it according to CPU type is more precise, but looks ugly. > > By "CPU type" do you mean microarchitecture here? Yes. > >> I am wondering if it worth to do. Maybe conservative selection is >> acceptable? > > Well, as I said earlier, I'd run it on a couple of different machines > and make FLUSHALL_BAR configurable from userspace - this way you have > real, solid data instead of guessing the exact number. Consider different CPU type has different balance point, I has another patch will add a interface for tuning. > >>> Also, have you run your patches with other benchmarks beside your >>> microbenchmark, say kernbench, SPEC<something>, i.e. some other >>> multithreaded benchmark touching shared memory? Are you seeing any >>> improvement there? >> >> I tested oltp reading and specjbb2005 with openjdk. They should not much >> flush_tlb_range calling. So, no clear improvement. >> Do you know benchmarks which cause enough flush_tlb_range? > > Not really. Probably get a couple of benchmarks and count > flush_tlb_range calls with trace_printk or perf probe? :-) perf probe is enough. :) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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