Messages in this thread Patch in this message | | | From | David Carrillo-Cisneros <> | Subject | [PATCH v3 10/15] perf header: make write_pmu_mappings pipe-mode friendly | Date | Tue, 6 Jun 2017 00:07:17 -0700 |
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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 <davidcc@google.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 f607c3c00f49..323ccd5df382 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; } -- 2.13.1.508.gb3defc5cc-goog
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