From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f54.google.com (mail-pa0-f54.google.com [209.85.220.54]) by kanga.kvack.org (Postfix) with ESMTP id D1C9082F66 for ; Mon, 5 Oct 2015 19:07:08 -0400 (EDT) Received: by pacfv12 with SMTP id fv12so193389661pac.2 for ; Mon, 05 Oct 2015 16:07:08 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id w14si43708970pbt.201.2015.10.05.16.07.07 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 05 Oct 2015 16:07:07 -0700 (PDT) Date: Tue, 6 Oct 2015 01:07:03 +0200 From: Jesper Dangaard Brouer Subject: Re: [MM PATCH V4.1 5/6] slub: support for bulk free with SLUB freelists Message-ID: <20151006010703.09e2f0ff@redhat.com> In-Reply-To: <20151005212045.GG26924@tassilo.jf.intel.com> References: <560ABE86.9050508@gmail.com> <20150930114255.13505.2618.stgit@canyon> <20151001151015.c59a1360c7720a257f655578@linux-foundation.org> <20151002114118.75aae2f9@redhat.com> <20151002154039.69f82bdc@redhat.com> <20151002145044.781c911ea98e3ea74ae5cf3b@linux-foundation.org> <20151005212639.35932b6c@redhat.com> <20151005212045.GG26924@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andi Kleen Cc: linux-mm@kvack.org, Christoph Lameter , netdev@vger.kernel.org, Arnaldo Carvalho de Melo , brouer@redhat.com (trimmed Cc list a little) On Mon, 5 Oct 2015 14:20:45 -0700 Andi Kleen wrote: > > My only problem left, is I want a perf measurement that pinpoint these > > kind of spots. The difference in L1-icache-load-misses were significant > > (1,278,276 vs 2,719,158). I tried to somehow perf record this with > > different perf events without being able to pinpoint the location (even > > though I know the spot now). Even tried Andi's ocperf.py... maybe he > > will know what event I should try? > > Run pmu-tools toplev.py -l3 with --show-sample. It tells you what the > bottle neck is and what to sample for if there is a suitable event and > even prints the command line. > > https://github.com/andikleen/pmu-tools/wiki/toplev-manual#sampling-with-toplev > My result from (IP-forward flow hitting CPU 0): $ sudo ./toplev.py -I 1000 -l3 -a --show-sample --core C0 So, what does this tell me?: C0 BAD Bad_Speculation: 0.00 % [ 5.50%] C0 BE Backend_Bound: 100.00 % [ 5.50%] C0 BE/Mem Backend_Bound.Memory_Bound: 53.06 % [ 5.50%] C0 BE/Core Backend_Bound.Core_Bound: 46.94 % [ 5.50%] C0-T0 FE Frontend_Bound.Frontend_Latency.Branch_Resteers: 5.42 % [ 5.50%] C0-T0 BE/Mem Backend_Bound.Memory_Bound.L1_Bound: 54.51 % [ 5.50%] C0-T0 BE/Core Backend_Bound.Core_Bound.Ports_Utilization: 20.99 % [ 5.60%] C0-T0 CPU utilization: 1.00 CPUs [100.00%] C0-T1 FE Frontend_Bound.Frontend_Latency.Branch_Resteers: 6.04 % [ 5.50%] C0-T1 CPU utilization: 1.00 CPUs [100.00%] Unfortunately the perf command it gives me fails with: "invalid or unsupported event". Perf command: perf record -g -e cpu/event=0xc5,umask=0x0,name=Branch_Resteers_BR_MISP_RETIRED_ALL_BRANCHES:pp,period=400009/pp,cpu/event=0xd,umask=0x3,cmask=1,name=Bad_Speculation_INT_MISC_RECOVERY_CYCLES,period=2000003/,cpu/event=0xd1,umask=0x1,name=L1_Bound_MEM_LOAD_UOPS_RETIRED_L1_HIT:pp,period=2000003/pp,cpu/event=0xd1,umask=0x40,name=L1_Bound_MEM_LOAD_UOPS_RETIRED_HIT_LFB:pp,period=100003/pp -C 0,4 -a > However frontend issues are difficult to sample, as they happen very far > away from instruction retirement where the sampling happens. So you may > have large skid and the sampling points may be far away. Skylake has new > special FRONTEND_* PEBS events for this, but before it was often difficult. This testlab CPU is i7-4790K @ 4.00GHz. Maybe I should get a Skylake... p.s. thanks for your pmu-tools[1], even-though I don't know how to use most of them ;-) -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer [1] https://github.com/andikleen/pmu-tools -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org