From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756426AbdGKXyk (ORCPT ); Tue, 11 Jul 2017 19:54:40 -0400 Received: from mail-pg0-f54.google.com ([74.125.83.54]:35032 "EHLO mail-pg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756392AbdGKXyh (ORCPT ); Tue, 11 Jul 2017 19:54:37 -0400 From: David Carrillo-Cisneros To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Andi Kleen , Simon Que , Wang Nan , Jiri Olsa , He Kuang , Masami Hiramatsu , David Ahern , Namhyung Kim , Stephane Eranian , Paul Turner , David Carrillo-Cisneros Subject: [PATCH v5 11/16] perf header: make write_pmu_mappings pipe-mode friendly Date: Tue, 11 Jul 2017 16:53:02 -0700 Message-Id: <20170711235307.99626-12-davidcc@google.com> X-Mailer: git-send-email 2.13.2.725.g09c95d1e9-goog In-Reply-To: <20170711235307.99626-1-davidcc@google.com> References: <20170711235307.99626-1-davidcc@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In pipe-mode, we will operate over a buffer instead of a file descriptor but write_pmu_mappings uses lseek to move over the perf.data file. Refactor write_pmu_mappings to avoid the usage of lseek and allow reusing the same logic in pipe-mode (next patch). Signed-off-by: David Carrillo-Cisneros --- tools/perf/util/header.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index e9f1d293d4ba..623cfbf72116 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -796,11 +796,19 @@ static int write_pmu_mappings(struct feat_fd *ff, struct perf_evlist *evlist __maybe_unused) { struct perf_pmu *pmu = NULL; - off_t offset = lseek(ff->fd, 0, SEEK_CUR); - __u32 pmu_num = 0; + u32 pmu_num = 0; int ret; - /* write real pmu_num later */ + /* + * Do a first pass to count number of pmu to avoid lseek so this + * works in pipe mode as well. + */ + while ((pmu = perf_pmu__scan(pmu))) { + if (!pmu->name) + continue; + pmu_num++; + } + ret = do_write(ff, &pmu_num, sizeof(pmu_num)); if (ret < 0) return ret; @@ -808,7 +816,6 @@ static int write_pmu_mappings(struct feat_fd *ff, while ((pmu = perf_pmu__scan(pmu))) { if (!pmu->name) continue; - pmu_num++; ret = do_write(ff, &pmu->type, sizeof(pmu->type)); if (ret < 0) @@ -819,12 +826,6 @@ static int write_pmu_mappings(struct feat_fd *ff, return ret; } - if (pwrite(ff->fd, &pmu_num, sizeof(pmu_num), offset) != sizeof(pmu_num)) { - /* discard all */ - lseek(ff->fd, offset, SEEK_SET); - return -1; - } - return 0; } -- 2.13.2.725.g09c95d1e9-goog