Commit-ID: a02c395cccc95e40b4c506c78857e24fdb049096 Gitweb: http://git.kernel.org/tip/a02c395cccc95e40b4c506c78857e24fdb049096 Author: David Carrillo-Cisneros <davi...@google.com> AuthorDate: Mon, 17 Jul 2017 21:25:44 -0700 Committer: Arnaldo Carvalho de Melo <a...@redhat.com> CommitDate: Tue, 18 Jul 2017 23:14:34 -0300
perf header: Make write_pmu_mappings pipe-mode friendly 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 <davi...@google.com> Acked-by: David Ahern <dsah...@gmail.com> Acked-by: Jiri Olsa <jo...@kernel.org> Cc: Alexander Shishkin <alexander.shish...@linux.intel.com> Cc: Andi Kleen <a...@linux.intel.com> Cc: He Kuang <heku...@huawei.com> Cc: Masami Hiramatsu <mhira...@kernel.org> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Paul Turner <p...@google.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Simon Que <s...@chromium.org> Cc: Stephane Eranian <eran...@google.com> Cc: Wang Nan <wangn...@huawei.com> Link: http://lkml.kernel.org/r/20170718042549.145161-12-davi...@google.com Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- 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 14db9f2..d5359e33 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -797,11 +797,19 @@ 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; @@ -809,7 +817,6 @@ 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) @@ -820,12 +827,6 @@ 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; }
