'perf test topo' is broken on my x86_64 system, with a rather cryptic message.
$ ./perf test -v topo
36: Test topology in session :
--- start ---
test child forked, pid 2705
templ file: /tmp/perf-test-6rSAkb
core_id number is too big. nr 9, cpu_nr 8. You may need to upgrade the perf tool.
test child interrupted
---- end ----
Test topology in session: FAILED!
$ ./perf --version
perf version 4.4.rc1.g34258a
(I included nr and cpu_nr values in the error message). The code (shown
below) is comparing a core_id value (nr) with number of cpus online (cpu_nr)
which don't seem to be related on this system.
On my system running 4.4.0-rc1 kernel, I have following cpus:
$ head /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 44
model name : Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
stepping : 2
microcode : 0x10
cpu MHz : 1596.000
cache size : 12288 KB
physical id : 0
$ ls -d /sys/devices/system/cpu/cpu?
/sys/devices/system/cpu/cpu0 /sys/devices/system/cpu/cpu4
/sys/devices/system/cpu/cpu1 /sys/devices/system/cpu/cpu5
/sys/devices/system/cpu/cpu2 /sys/devices/system/cpu/cpu6
/sys/devices/system/cpu/cpu3 /sys/devices/system/cpu/cpu7
$ cat /sys/devices/system/cpu/online
0-7
$ cat /sys/devices/system/cpu/cpu?/topology/core_id
0
1
9
10
0
1
9
10
Commenting out following code seems to cause the test to pass, but are
core_ids in general related to number of cpus online?
Sukadev
---
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 4383800..d5104da 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1652,11 +1652,14 @@ static int process_cpu_topology(struct perf_file_section *section,
if (ph->needs_swap)
nr = bswap_32(nr);
+#if 0
if (nr > (u32)cpu_nr) {
- pr_debug("core_id number is too big."
- "You may need to upgrade the perf tool.\n");
+ pr_debug("core_id number is too big. nr %d, cpu_nr %d. "
+ "You may need to upgrade the perf tool.\n",
+ nr, cpu_nr);
goto free_cpu;
}
+#endif
ph->env.cpu[i].core_id = nr;
ret = readn(fd, &nr, sizeof(nr));
On Thu, Nov 19, 2015 at 02:13:53PM -0800, Sukadev Bhattiprolu wrote:
SNIP
>
> $ cat /sys/devices/system/cpu/online
> 0-7
>
> $ cat /sys/devices/system/cpu/cpu?/topology/core_id
> 0
> 1
> 9
> 10
> 0
> 1
> 9
> 10
we assume the actualy core_id number is within 0 - [cpu-max-number]
how can one reach above core_id setup? ;-)
thanks,
jirka
On Thu, Nov 19, 2015 at 02:13:53PM -0800, Sukadev Bhattiprolu wrote:
SNIP
> Commenting out following code seems to cause the test to pass, but are
> core_ids in general related to number of cpus online?
>
> Sukadev
>
> ---
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 4383800..d5104da 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -1652,11 +1652,14 @@ static int process_cpu_topology(struct perf_file_section *section,
> if (ph->needs_swap)
> nr = bswap_32(nr);
>
> +#if 0
> if (nr > (u32)cpu_nr) {
> - pr_debug("core_id number is too big."
> - "You may need to upgrade the perf tool.\n");
> + pr_debug("core_id number is too big. nr %d, cpu_nr %d. "
> + "You may need to upgrade the perf tool.\n",
> + nr, cpu_nr);
> goto free_cpu;
> }
> +#endif
> ph->env.cpu[i].core_id = nr;
looks like we can safely remove this check,
I don't see any place we use core_id as array index
or any other place assuming core_id < cpu_nr
Kan Liang?
thanks,
jirka
>
> On Thu, Nov 19, 2015 at 02:13:53PM -0800, Sukadev Bhattiprolu wrote:
>
> SNIP
>
> > Commenting out following code seems to cause the test to pass, but are
> > core_ids in general related to number of cpus online?
> >
> > Sukadev
> >
> > ---
> > diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index
> > 4383800..d5104da 100644
> > --- a/tools/perf/util/header.c
> > +++ b/tools/perf/util/header.c
> > @@ -1652,11 +1652,14 @@ static int process_cpu_topology(struct
> perf_file_section *section,
> > if (ph->needs_swap)
> > nr = bswap_32(nr);
> >
> > +#if 0
> > if (nr > (u32)cpu_nr) {
> > - pr_debug("core_id number is too big."
> > - "You may need to upgrade the perf tool.\n");
> > + pr_debug("core_id number is too big. nr %d, cpu_nr %d. "
> > + "You may need to upgrade the perf tool.\n",
> > + nr, cpu_nr);
> > goto free_cpu;
> > }
> > +#endif
> > ph->env.cpu[i].core_id = nr;
>
> looks like we can safely remove this check,
>
> I don't see any place we use core_id as array index or any other place
> assuming core_id < cpu_nr
>
> Kan Liang?
I assumed that the core_id should be less than max_cpu_number.
But in your case it looks the assumption doesn't work.
I think we can safely remove the check as Jirka suggested.
Thanks,
Kan