Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753136Ab1C1BCp (ORCPT ); Sun, 27 Mar 2011 21:02:45 -0400 Received: from mail9.hitachi.co.jp ([133.145.228.44]:50902 "EHLO mail9.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751916Ab1C1BCo (ORCPT ); Sun, 27 Mar 2011 21:02:44 -0400 X-AuditID: b753bd60-a32b8ba000004916-0e-4d8fde31c665 X-AuditID: b753bd60-a32b8ba000004916-0e-4d8fde31c665 Message-ID: <4D8FDE2E.8080009@hitachi.com> Date: Mon, 28 Mar 2011 10:02:38 +0900 From: Masami Hiramatsu Organization: Systems Development Lab., Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; ja; rv:1.9.2.15) Gecko/20110303 Thunderbird/3.1.9 MIME-Version: 1.0 To: Lin Ming Cc: Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , linux-kernel Subject: Re: [PATCH -tip v3] perf probe: Add fastpath to do lookup by function name References: <1301041668.14111.52.camel@minggr.sh.intel.com> In-Reply-To: <1301041668.14111.52.camel@minggr.sh.intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6049 Lines: 201 (2011/03/25 17:27), Lin Ming wrote: > v3 -> v2: > - Make pubname_search_cb more generic > - Add fastpath to find_probes also Good catch! :) Acked-by: Masami Hiramatsu Thank you, > > v2 -> v1: > - Don't compare file names with cu_find_realpath(...), instead, compare > them with the name returned by dwarf_decl_file(sp_die) > > The vmlinux file may have thousands of CUs. > We can lookup function name from .debug_pubnames section > to avoid the slow loop on CUs. > > 1. Improvement data for find_line_range > > ./perf stat -e cycles -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 > ===================== > 847,988,276 cycles > > 0.355075856 seconds time elapsed > > after patch applied > ===================== > 206,102,622 cycles > > 0.086883555 seconds time elapsed > > 2. Improvement data for find_probes > > ./perf stat -e cycles -r 10 -- ./perf probe -k /home/mlin/vmlinux \ > -s /home/mlin/linux-2.6 \ > --vars csum_partial_copy_to_user > tmp.log > > before patch applied > ===================== > 848,490,844 cycles > > 0.355307901 seconds time elapsed > > after patch applied > ===================== > 205,684,469 cycles > > 0.086694010 seconds time elapsed > > Signed-off-by: Lin Ming > --- > tools/perf/util/probe-finder.c | 68 ++++++++++++++++++++++++++++++++++++++++ > tools/perf/util/probe-finder.h | 2 + > 2 files changed, 70 insertions(+), 0 deletions(-) > > diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c > index 194f9e2..23fc9eb 100644 > --- a/tools/perf/util/probe-finder.c > +++ b/tools/perf/util/probe-finder.c > @@ -1435,6 +1435,38 @@ static int find_probe_point_by_func(struct probe_finder *pf) > return _param.retval; > } > > +struct pubname_callback_param { > + char *function; > + char *file; > + Dwarf_Die *cu_die; > + Dwarf_Die *sp_die; > + int found; > +}; > + > +static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data) > +{ > + struct pubname_callback_param *param = data; > + > + if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) { > + if (dwarf_tag(param->sp_die) != DW_TAG_subprogram) > + return DWARF_CB_OK; > + > + if (die_compare_name(param->sp_die, param->function)) { > + if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die)) > + return DWARF_CB_OK; > + > + if (param->file && > + strtailcmp(param->file, dwarf_decl_file(param->sp_die))) > + return DWARF_CB_OK; > + > + param->found = 1; > + return DWARF_CB_ABORT; > + } > + } > + > + return DWARF_CB_OK; > +} > + > /* Find probe points from debuginfo */ > static int find_probes(int fd, struct probe_finder *pf) > { > @@ -1461,6 +1493,23 @@ static int find_probes(int fd, struct probe_finder *pf) > > off = 0; > line_list__init(&pf->lcache); > + > + /* Fastpath: lookup by function name from .debug_pubnames section */ > + if (pp->function) { > + struct pubname_callback_param pubname_param = { > + .function = pp->function, .file = pp->file, > + .cu_die = &pf->cu_die, .sp_die = &pf->sp_die, .found = 0}; > + struct dwarf_callback_param probe_param = { > + .data = (void *)pf, .retval = 0}; > + > + dwarf_getpubnames(dbg, pubname_search_cb, &pubname_param, 0); > + if (pubname_param.found) { > + ret = probe_point_search_cb(&pf->sp_die, &probe_param); > + if (ret) > + goto found; > + } > + } > + > /* Loop on CUs (Compilation Unit) */ > while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL)) { > /* Get the DIE(Debugging Information Entry) of this CU */ > @@ -1488,6 +1537,8 @@ static int find_probes(int fd, struct probe_finder *pf) > } > off = noff; > } > + > +found: > line_list__free(&pf->lcache); > if (dwfl) > dwfl_end(dwfl); > @@ -1895,6 +1946,22 @@ 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 pubname_callback_param pubname_param = { > + .function = lr->function, .file = lr->file, > + .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0}; > + struct dwarf_callback_param line_range_param = { > + .data = (void *)&lf, .retval = 0}; > + > + dwarf_getpubnames(dbg, pubname_search_cb, &pubname_param, 0); > + if (pubname_param.found) { > + line_range_search_cb(&lf.sp_die, &line_range_param); > + 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 +1990,7 @@ 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..605730a 100644 > --- a/tools/perf/util/probe-finder.h > +++ b/tools/perf/util/probe-finder.h > @@ -49,6 +49,7 @@ struct probe_finder { > Dwarf_Addr addr; /* Address */ > const char *fname; /* Real file name */ > Dwarf_Die cu_die; /* Current CU */ > + Dwarf_Die sp_die; > struct list_head lcache; /* Line cache for lazy match */ > > /* For variable searching */ > @@ -83,6 +84,7 @@ 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; > }; > -- Masami HIRAMATSU 2nd Dept. Linux Technology Center Hitachi, Ltd., Systems Development Laboratory E-mail: masami.hiramatsu.pt@hitachi.com -- 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/