Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933775Ab1CXIjF (ORCPT ); Thu, 24 Mar 2011 04:39:05 -0400 Received: from mga11.intel.com ([192.55.52.93]:26317 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933710Ab1CXIjD (ORCPT ); Thu, 24 Mar 2011 04:39:03 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.63,236,1299484800"; d="scan'208";a="901014981" Subject: Re: [PATCH] perf probe: Add fastpath to do lookup by function name From: Lin Ming To: Ingo Molnar Cc: Arnaldo Carvalho de Melo , Masami Hiramatsu , Peter Zijlstra , linux-kernel In-Reply-To: <20110324075830.GA28885@elte.hu> References: <1300981134-7333-1-git-send-email-ming.m.lin@intel.com> <20110324075830.GA28885@elte.hu> Content-Type: text/plain; charset="UTF-8" Date: Thu, 24 Mar 2011 16:38:43 +0800 Message-ID: <1300955923.14111.29.camel@minggr.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4924 Lines: 147 On Thu, 2011-03-24 at 15:58 +0800, Ingo Molnar wrote: > * Lin Ming wrote: > > > The vmlinux file may have thousands of CUs. > > We can lookup function name from .debug_pubnames section > > to avoid the slow loop on CUs. > > Mind including before/after perf stat --repeat 10 results in the changelog, of > an affected command which got faster? >From 611a823a34e655d47a80f92994b004391e2b244c Mon Sep 17 00:00:00 2001 From: Lin Ming Date: Thu, 24 Mar 2011 23:22:24 +0800 Subject: [PATCH] perf probe: Add fastpath to do lookup by function name The vmlinux file may have thousands of CUs. We can lookup function name from .debug_pubnames section to avoid the slow loop on CUs. ./perf stat -r 10 -- ./perf probe -k /home/mlin/vmlinux \ -s /home/mlin/linux-2.6 \ --line csum_partial_copy_to_user > tmp.log before patch applied ===================== 364.535892 task-clock-msecs # 0.997 CPUs 0 context-switches # 0.000 M/sec 0 CPU-migrations # 0.000 M/sec 29,993 page-faults # 0.082 M/sec 865,862,109 cycles # 2375.245 M/sec 1,255,259,630 instructions # 1.450 IPC 252,400,884 branches # 692.390 M/sec 3,429,376 branch-misses # 1.359 % 1,386,990 cache-references # 3.805 M/sec 687,188 cache-misses # 1.885 M/sec 0.365792170 seconds time elapsed after patch applied ===================== 89.896405 task-clock-msecs # 0.991 CPUs 1 context-switches # 0.000 M/sec 0 CPU-migrations # 0.000 M/sec 10,145 page-faults # 0.113 M/sec 214,553,875 cycles # 2386.679 M/sec 226,915,559 instructions # 1.058 IPC 44,536,614 branches # 495.422 M/sec 613,074 branch-misses # 1.377 % 860,787 cache-references # 9.575 M/sec 442,380 cache-misses # 4.921 M/sec 0.090716032 seconds time elapsed Signed-off-by: Lin Ming --- tools/perf/util/probe-finder.c | 38 ++++++++++++++++++++++++++++++++++++++ tools/perf/util/probe-finder.h | 1 + 2 files changed, 39 insertions(+), 0 deletions(-) diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index 194f9e2..b2034c2 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -1876,6 +1876,30 @@ static int find_line_range_by_func(struct line_finder *lf) return param.retval; } +static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data) +{ + struct line_finder *lf = data; + struct line_range *lr = lf->lr; + + if (dwarf_offdie(dbg, gl->die_offset, &lf->sp_die)) { + if (dwarf_tag(&lf->sp_die) != DW_TAG_subprogram) + return DWARF_CB_OK; + + if (die_compare_name(&lf->sp_die, lr->function)) { + if (!dwarf_offdie(dbg, gl->cu_offset, &lf->cu_die)) + return DWARF_CB_OK; + + if (lr->file && !cu_find_realpath(&lf->cu_die, lr->file)) + return DWARF_CB_OK; + + lf->found = 1; + return DWARF_CB_ABORT; + } + } + + return DWARF_CB_OK; +} + int find_line_range(int fd, struct line_range *lr) { struct line_finder lf = {.lr = lr, .found = 0}; @@ -1895,6 +1919,19 @@ int find_line_range(int fd, struct line_range *lr) return -EBADF; } + /* Fastpath: lookup by function name from .debug_pubnames section */ + if (lr->function) { + struct dwarf_callback_param param = {.data = (void *)&lf, .retval = 0}; + + dwarf_getpubnames(dbg, pubname_search_cb, &lf, 0); + if (lf.found) { + lf.found = 0; + line_range_search_cb(&lf.sp_die, ¶m); + if (lf.found) + goto found; + } + } + /* Loop on CUs (Compilation Unit) */ while (!lf.found && ret >= 0) { if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0) @@ -1923,6 +1960,7 @@ int find_line_range(int fd, struct line_range *lr) off = noff; } +found: /* Store comp_dir */ if (lf.found) { comp_dir = cu_get_comp_dir(&lf.cu_die); diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h index beaefc3..4bc56a4 100644 --- a/tools/perf/util/probe-finder.h +++ b/tools/perf/util/probe-finder.h @@ -83,6 +83,7 @@ struct line_finder { int lno_s; /* Start line number */ int lno_e; /* End line number */ Dwarf_Die cu_die; /* Current CU */ + Dwarf_Die sp_die; int found; }; -- 1.7.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/