From c3a057dc3aa9979ce6dc350e05eb2e4c021432cd Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Mon, 19 Jul 2021 15:31:52 -0700 Subject: perf inject: Fix output from a file to a pipe When the input is a regular file but the output is a pipe, it should write a pipe header. But just repiping would write a portion of the existing header which is different in 'size' value. So we need to prevent it and write a new pipe header along with other information like event attributes and features. This can handle something like this: # perf record -a -B sleep 1 # perf inject -b -i perf.data | perf report -i - Factor out perf_event__synthesize_for_pipe() to be shared between perf record and inject. Signed-off-by: Namhyung Kim Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Andi Kleen Cc: Ian Rogers Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/20210719223153.1618812-5-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-inject.c | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) (limited to 'tools/perf/builtin-inject.c') diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c index f9af24350f61..6ad191e731fc 100644 --- a/tools/perf/builtin-inject.c +++ b/tools/perf/builtin-inject.c @@ -919,6 +919,7 @@ int cmd_inject(int argc, const char **argv) .use_stdio = true, }; int ret; + bool repipe = true; struct option options[] = { OPT_BOOLEAN('b', "build-ids", &inject.build_ids, @@ -993,10 +994,18 @@ int cmd_inject(int argc, const char **argv) } data.path = inject.input_name; - if (!strcmp(inject.input_name, "-") || inject.output.is_pipe) + if (!strcmp(inject.input_name, "-") || inject.output.is_pipe) { inject.is_pipe = true; + /* + * Do not repipe header when input is a regular file + * since either it can rewrite the header at the end + * or write a new pipe header. + */ + if (strcmp(inject.input_name, "-")) + repipe = false; + } - inject.session = __perf_session__new(&data, inject.is_pipe, + inject.session = __perf_session__new(&data, repipe, perf_data__fd(&inject.output), &inject.tool); if (IS_ERR(inject.session)) { @@ -1007,6 +1016,21 @@ int cmd_inject(int argc, const char **argv) if (zstd_init(&(inject.session->zstd_data), 0) < 0) pr_warning("Decompression initialization failed.\n"); + if (!data.is_pipe && inject.output.is_pipe) { + ret = perf_header__write_pipe(perf_data__fd(&inject.output)); + if (ret < 0) { + pr_err("Couldn't write a new pipe header.\n"); + goto out_delete; + } + + ret = perf_event__synthesize_for_pipe(&inject.tool, + inject.session, + &inject.output, + perf_event__repipe); + if (ret < 0) + goto out_delete; + } + if (inject.build_ids && !inject.build_id_all) { /* * to make sure the mmap records are ordered correctly -- cgit