Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1664406

[PATCH v4 11/16] perf header: make write_pmu_mappings pipe-mode friendly

Show all headers | View raw

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 a02959c78067..deb02343fccf 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

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v4 00/16] perf tool: add meta-data header support for pipe-mode David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
  [PATCH v4 16/16] perf header: add event desc to pipe-mode header David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
  [PATCH v4 03/16] perf header: fail on write_padded error David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
  [PATCH v4 13/16] perf header: change FEAT_OP* macros David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
  [PATCH v4 02/16] perf header: add PROCESS_STR_FUN macro David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
  [PATCH v4 10/16] perf header: use struct feat_fd in read header records David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
  [PATCH v4 07/16] perf header: use struct feat_fd for print David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
  [PATCH v4 01/16] perf header: encapsulate read and swap David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
  [PATCH v4 04/16] perf util: add const modifier to buf in "writen" function David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
  [PATCH v4 11/16] perf header: make write_pmu_mappings pipe-mode friendly David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
  [PATCH v4 09/16] perf header: don't pass struct perf_file_section to process_##_feat David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
    Re: [PATCH v4 09/16] perf header: don't pass struct  perf_file_section to process_##_feat Jiri Olsa <jolsa@redhat.com> - 2017-06-13 21:00 +0200
      Re: [PATCH v4 09/16] perf header: don't pass struct perf_file_section  to process_##_feat David Carrillo-Cisneros <davidcc@google.com> - 2017-06-14 04:00 +0200
  [PATCH v4 12/16] perf header: add a buffer to struct feat_fd David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
    Re: [PATCH v4 12/16] perf header: add a buffer to struct feat_fd Jiri Olsa <jolsa@redhat.com> - 2017-06-13 21:00 +0200
      Re: [PATCH v4 12/16] perf header: add a buffer to struct feat_fd David Carrillo-Cisneros <davidcc@google.com> - 2017-06-14 04:00 +0200
  [PATCH v4 14/16] perf tool: add show_feature_header to perf_tool David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
    Re: [PATCH v4 14/16] perf tool: add show_feature_header to perf_tool Jiri Olsa <jolsa@redhat.com> - 2017-06-13 21:00 +0200
  [PATCH v4 06/16] perf header: add struct feat_fd for write David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
  [PATCH v4 08/16] perf header: use struct feat_fd to process header records David Carrillo-Cisneros <davidcc@google.com> - 2017-06-13 06:40 +0200
  Re: [PATCH v4 00/16] perf tool: add meta-data header support for  pipe-mode Jiri Olsa <jolsa@redhat.com> - 2017-06-13 21:00 +0200
    Re: [PATCH v4 00/16] perf tool: add meta-data header support for pipe-mode David Carrillo-Cisneros <davidcc@google.com> - 2017-06-14 08:50 +0200
  Re: [PATCH v4 00/16] perf tool: add meta-data header support for  pipe-mode Jiri Olsa <jolsa@redhat.com> - 2017-06-13 21:00 +0200
    Re: [PATCH v4 00/16] perf tool: add meta-data header support for pipe-mode David Carrillo-Cisneros <davidcc@google.com> - 2017-06-14 09:00 +0200
      Re: [PATCH v4 00/16] perf tool: add meta-data header support for  pipe-mode Jiri Olsa <jolsa@redhat.com> - 2017-06-14 09:30 +0200
        Re: [PATCH v4 00/16] perf tool: add meta-data header support for pipe-mode David Carrillo-Cisneros <davidcc@google.com> - 2017-06-14 20:40 +0200

csiph-web