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perf header: Make write_pmu_mappings pipe-mode friendly

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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>
Acked-by: David Ahern <dsahern@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Que <sque@chromium.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20170718042549.145161-12-davidcc@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
David Carrillo-Cisneros
2017-07-17 21:25:44 -07:00
committed by Arnaldo Carvalho de Melo
parent 48e5fcea38
commit a02c395ccc
1 changed files with 11 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
tools/perf/util/header.c
View File

@@ -797,11 +797,19 @@ static int write_pmu_mappings(struct feat_fd *ff,
struct perf_evlist *evlist __maybe_unused) struct perf_evlist *evlist __maybe_unused)
{ {
struct perf_pmu *pmu = NULL; struct perf_pmu *pmu = NULL;
off_t offset = lseek(ff->fd, 0, SEEK_CUR); u32 pmu_num = 0;
__u32 pmu_num = 0;
int ret; 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)); ret = do_write(ff, &pmu_num, sizeof(pmu_num));
if (ret < 0) if (ret < 0)
return ret; return ret;
@@ -809,7 +817,6 @@ static int write_pmu_mappings(struct feat_fd *ff,
while ((pmu = perf_pmu__scan(pmu))) { while ((pmu = perf_pmu__scan(pmu))) {
if (!pmu->name) if (!pmu->name)
continue; continue;
pmu_num++;
ret = do_write(ff, &pmu->type, sizeof(pmu->type)); ret = do_write(ff, &pmu->type, sizeof(pmu->type));
if (ret < 0) if (ret < 0)
@@ -820,12 +827,6 @@ static int write_pmu_mappings(struct feat_fd *ff,
return ret; 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; return 0;
} }