3.2.72-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
commit caa470475d9b59eeff093ae650800d34612c4379 upstream.
The original patch introducing this header wrote the number of CPUs available
and online in one order and then swapped those values when reading, fix it.
Before:
# perf record usleep 1
# perf report --header-only | grep 'nrcpus \(online\|avail\)'
# nrcpus online : 4
# nrcpus avail : 4
# echo 0 > /sys/devices/system/cpu/cpu2/online
# perf record usleep 1
# perf report --header-only | grep 'nrcpus \(online\|avail\)'
# nrcpus online : 4
# nrcpus avail : 3
# echo 0 > /sys/devices/system/cpu/cpu1/online
# perf record usleep 1
# perf report --header-only | grep 'nrcpus \(online\|avail\)'
# nrcpus online : 4
# nrcpus avail : 2
After the fix, bringing back the CPUs online:
# perf report --header-only | grep 'nrcpus \(online\|avail\)'
# nrcpus online : 2
# nrcpus avail : 4
# echo 1 > /sys/devices/system/cpu/cpu2/online
# perf record usleep 1
# perf report --header-only | grep 'nrcpus \(online\|avail\)'
# nrcpus online : 3
# nrcpus avail : 4
# echo 1 > /sys/devices/system/cpu/cpu1/online
# perf record usleep 1
# perf report --header-only | grep 'nrcpus \(online\|avail\)'
# nrcpus online : 4
# nrcpus avail : 4
Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Fixes: fbe96f29ce4b ("perf tools: Make perf.data more self-descriptive (v8)")
Link: http://lkml.kernel.org/r/20150911153323.GP23511@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
[bwh: Backported to 3.2: print_nrcpus() reads and prints these fields
immediately, so read both of them into an array before printing them in
reverse order.]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
tools/perf/util/header.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -796,25 +796,19 @@ static void print_cpudesc(struct perf_he
static void print_nrcpus(struct perf_header *ph, int fd, FILE *fp)
{
ssize_t ret;
- u32 nr;
+ u32 nr[2];
ret = read(fd, &nr, sizeof(nr));
if (ret != (ssize_t)sizeof(nr))
- nr = -1; /* interpreted as error */
+ nr[0] = nr[1] = -1; /* interpreted as error */
- if (ph->needs_swap)
- nr = bswap_32(nr);
+ if (ph->needs_swap) {
+ nr[0] = bswap_32(nr[0]);
+ nr[1] = bswap_32(nr[1]);
+ }
- fprintf(fp, "# nrcpus online : %u\n", nr);
-
- ret = read(fd, &nr, sizeof(nr));
- if (ret != (ssize_t)sizeof(nr))
- nr = -1; /* interpreted as error */
-
- if (ph->needs_swap)
- nr = bswap_32(nr);
-
- fprintf(fp, "# nrcpus avail : %u\n", nr);
+ fprintf(fp, "# nrcpus online : %u\n", nr[1]);
+ fprintf(fp, "# nrcpus avail : %u\n", nr[0]);
}
static void print_version(struct perf_header *ph, int fd, FILE *fp)
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html