Commit ed307758 authored Oct 16, 2014 by Wang Nan Committed by Arnaldo Carvalho de Melo Oct 29, 2014

perf tools: Ensure return negative value when write header error

When 'perf record' write headers, it calls write_xxx in
tools/perf/util/header.c, and check return value. It rolls back all
working only when return value is negative.

This patch ensures write_cpudesc() and write_total_mem() return negative number
when error. Without this patch, headers reported by 'perf report' header is
error in some platform. Following output is caputured on ARM, which doesn't
contain "Processor" field in /proc/cpuinfo. See "cpudesc", "total memory" and
"cmdline" field.

   bash-4.2# perf record ls
   ...
   [ perf record: Woken up 1 times to write data ]
   [ perf record: Captured and wrote 0.001 MB perf.data (~36 samples) ]
   bash-4.2# perf report --stdio --header
   Error:
   The perf.data file has no samples!
   # ========
   # captured on: Fri Sep 12 10:09:10 2014
   # hostname : arma15el
   # os release : 3.17.0+
   # perf version : 3.10.53
   # arch : armv7l
   # nrcpus online : 4
   # nrcpus avail : 1
   # cpudesc : (null)
   # total memory : 0 kB
   # cmdline :
   # event : name = cycles, type = 0, config = 0x0, config1 = 0x0, config2 = 0x0, excl_usr = 0, excl_kern = 0, excl_host = 0, excl_guest = 1, precise_ip = 0
   # pmu mappings: not available
   # ========
   #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Waiman Long <Waiman.Long@hp.com>
Link: http://lkml.kernel.org/r/1413428909-80017-1-git-send-email-wangnan0@huawei.com


Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 13dcbbc0

tools/perf/util/header.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -601,8 +601,10 @@ static int __write_cpudesc(int fd, const char *cpuinfo_proc)
		break;
		}

		if (ret)
		if (ret) {
		ret = -1;
		goto done;
		}

		s = buf;

		@@ -965,7 +967,8 @@ static int write_total_mem(int fd, struct perf_header *h __maybe_unused,
		n = sscanf(buf, "%*s %"PRIu64, &mem);
		if (n == 1)
		ret = do_write(fd, &mem, sizeof(mem));
		}
		} else
		ret = -1;
		free(buf);
		fclose(fp);
		return ret;

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