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authorArtem Bityutskiy <artem.bityutskiy@linux.intel.com>2018-07-25 11:52:06 +0300
committerLen Brown <len.brown@intel.com>2018-07-26 14:20:39 -0400
commit4f206a0fabc3e806349add0996b3a999739559d2 (patch)
tree2623818ee7da7a05f507126d6a2583fb94fd4baf
parent9d83601a9cc1884d1b5706ee2acc661d558c6838 (diff)
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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>
-rw-r--r--tools/power/x86/turbostat/turbostat.c2
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)