Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756762Ab2EYVtK (ORCPT ); Fri, 25 May 2012 17:49:10 -0400 Received: from casper.infradead.org ([85.118.1.10]:40724 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755907Ab2EYVtI (ORCPT ); Fri, 25 May 2012 17:49:08 -0400 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , David Ahern , Frederic Weisbecker , Mike Galbraith , Namhyung Kim , Paul Mackerras , Peter Zijlstra , Stephane Eranian Subject: [PATCH 3/5 v2] perf top: Fix counter name fixup when fallbacking to cpu-clock Date: Fri, 25 May 2012 18:48:57 -0300 Message-Id: <1337982539-2882-4-git-send-email-acme@infradead.org> X-Mailer: git-send-email 1.7.9.2.358.g22243 In-Reply-To: <1337982539-2882-1-git-send-email-acme@infradead.org> References: <1337982539-2882-1-git-send-email-acme@infradead.org> Content-Type: text/plain; charset="UTF-8" X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2304 Lines: 58 From: Arnaldo Carvalho de Melo In 40491eaa "perf top: Update event name when falling back to cpu-clock" we freed counter->name but didn't reset it to NULL, then when setting it to the result of event_name(), event_name() would use the cached value, which by now was overwritten and thus we got garbage or a zero lenght string. Fix it by just freeing and setting counter->name to NULL, this way event_name() when called afterwards, will find the right counter name and cache it again. Found while trying 'cycles:pp' on a machine were :pp couldn't be honoured. Probably the best fallback here is to tell the user that that level of precision is not available on the PMU and then go removing 'p', levels of precision till we get to play 'cycles' and if even that fails, _then_ get to 'cpu-clock'. But that is the matter for another patch, this one just needs to fix the caching issue, which in the end will show 'cpu-clock' when tools ask for the event name being used, which clarifies things for the user, that will see that 'cycles:pp' or whatever not support event is not being used, some sort of fallback happened. Cc: David Ahern Cc: Frederic Weisbecker Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-w1neie2dqli89we1bzwkf4id@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-top.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index 6031dce..d4a5f9b 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -953,7 +953,7 @@ try_again: attr->config = PERF_COUNT_SW_CPU_CLOCK; if (counter->name) { free(counter->name); - counter->name = strdup(event_name(counter)); + counter->name = NULL; } goto try_again; } -- 1.7.9.2.358.g22243 -- 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/