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| author | Artem Bityutskiy <artem.bityutskiy@linux.intel.com> | 2018-07-25 10:52:06 +0200 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2018-07-26 20:20:39 +0200 |
| commit | 4f206a0fabc3e806349add0996b3a999739559d2 (patch) | |
| tree | 2623818ee7da7a05f507126d6a2583fb94fd4baf /tools/power | |
| parent | tools/power turbostat: fix -S on UP systems (diff) | |
| download | linux-4f206a0fabc3e806349add0996b3a999739559d2.tar.xz linux-4f206a0fabc3e806349add0996b3a999739559d2.zip | |
tools/power turbostat: fix bogus summary values
This patch fixes a regression introduced in
commit 8cb48b32a5de ("tools/power turbostat: track thread ID in cpu_topology")
Turbostat uses incorrect cores number ('topo.num_cores') - its value is count
of logical CPUs, instead of count of physical cores. So it is twice as large as
it should be on a typical Intel system. For example, on a 6 core Xeon system
'topo.num_cores' is 12, and on a 52 core Xeon system 'topo.num_cores' is 104.
And interestingly, on a 68-core Knights Landing Intel system 'topo.num_cores'
is 272, because this system has 4 logical CPUs per core.
As a result, some of the turbostat calculations are incorrect. For example,
on idle 52-core Xeon system when all cores are ~99% in Core C6 (CPU%c6), the
summary (very first) line shows ~48% Core C6, while it should be ~99%.
This patch fixes the problem by fixing 'topo.num_cores' calculation.
Was:
1. Init 'thread_id' for all CPUs to -1
2. Run 'get_thread_siblings()' which sets it to 0 or 1
3. Increment 'topo.num_cores' when thread_id != -1 (bug!)
Now:
1. Init 'thread_id' for all CPUs to -1
2. Run 'get_thread_siblings()' which sets it to 0 or 1
3. Increment 'topo.num_cores' when thread_id is not 0
I did not have a chance to test this on an AMD machine, and only tested on a
couple of Intel Xeons (6 and 52 cores).
Reported-by: Vladislav Govtva <vladislav.govtva@intel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'tools/power')
| -rw-r--r-- | tools/power/x86/turbostat/turbostat.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c index 81a1df0fb5e2..1b53a2489ebb 100644 --- a/tools/power/x86/turbostat/turbostat.c +++ b/tools/power/x86/turbostat/turbostat.c @@ -4838,7 +4838,7 @@ void topology_probe() siblings = get_thread_siblings(&cpus[i]); if (siblings > max_siblings) max_siblings = siblings; - if (cpus[i].thread_id != -1) + if (cpus[i].thread_id == 0) topo.num_cores++; if (debug > 1) |