From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751554AbaI2IfM (ORCPT ); Mon, 29 Sep 2014 04:35:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20330 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750970AbaI2IfK (ORCPT ); Mon, 29 Sep 2014 04:35:10 -0400 Date: Mon, 29 Sep 2014 10:34:52 +0200 From: Jiri Olsa To: Namhyung Kim Cc: Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , Paul Mackerras , Namhyung Kim , LKML , Arun Sharma , David Ahern , Frederic Weisbecker , Jean Pihet Subject: Re: [PATCH v2 1/2] perf callchain: Create an address space per thread Message-ID: <20140929083452.GA1223@krava.brq.redhat.com> References: <1411966692-26648-1-git-send-email-namhyung@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1411966692-26648-1-git-send-email-namhyung@kernel.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 29, 2014 at 01:58:11PM +0900, Namhyung Kim wrote: > The unw_addr_space_t in libunwind represents an address space to be > used for stack unwinding. It doesn't need to be create/destory > everytime to unwind callchain (as in get_entries) and can have a same > lifetime as thread (unless exec called). > > So move the address space construction/destruction logic to the thread > lifetime handling functions. This is a preparation to enable caching > in the unwind library. > > Note that it saves unw_addr_space_t object using thread__set_priv(). > It seems currently only used by perf trace and perf kvm stat commands > which don't use callchain. > > Acked-by: Jean Pihet > Cc: Jiri Olsa > Cc: Arun Sharma > Cc: David Ahern > Cc: Frederic Weisbecker > Signed-off-by: Namhyung Kim > --- > tools/perf/util/thread.c | 6 ++++++ > tools/perf/util/unwind-libunwind.c | 30 +++++++++++++++++++++++++----- > tools/perf/util/unwind.h | 17 +++++++++++++++++ > 3 files changed, 48 insertions(+), 5 deletions(-) > > diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c > index a9df7f2c6dc9..2b7b2d91c016 100644 > --- a/tools/perf/util/thread.c > +++ b/tools/perf/util/thread.c > @@ -7,6 +7,7 @@ > #include "util.h" > #include "debug.h" > #include "comm.h" > +#include "unwind.h" > > int thread__init_map_groups(struct thread *thread, struct machine *machine) > { > @@ -37,6 +38,9 @@ struct thread *thread__new(pid_t pid, pid_t tid) > thread->cpu = -1; > INIT_LIST_HEAD(&thread->comm_list); > > + if (unwind__prepare_access(thread) < 0) > + goto err_thread; So this is something we need to do only for DWARF unwind via libunwind. Do we want some condition to bypass this in for the rest of the cases? I think we could check for symbol_conf.use_callchain and for the PERF_SAMPLE_REGS_USER|PERF_SAMPLE_STACK_USER sample types in evlist, something like: bool has_dwarf_data_for_callchains = symbol_conf.use_callchain && evlist_sample_type_has(evlist, PERF_SAMPLE_REGS_USER|PERF_SAMPLE_STACK_USER) ;-) thanks, jirka