47 lines
1.8 KiB
Diff
47 lines
1.8 KiB
Diff
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commit dee15756bcb287ccf39a904be07c90107b13844b
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Author: Laurent Dufour <ldufour@linux.ibm.com>
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Date: Wed May 3 10:50:15 2023 +0200
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lparstat: Fix offline threads uninitialized entries
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When some threads are offline, lparstat -E is failing like that:
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$ ppc64_cpu --info # CPU 20 is offline
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Core 0: 0* 1* 2* 3* 4* 5* 6* 7*
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Core 1: 8* 9* 10* 11* 12* 13* 14* 15*
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Core 2: 16* 17* 18* 19* 20 21* 22* 23*
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Core 3: 24* 25* 26* 27* 28* 29* 30* 31*
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Core 4: 32* 33* 34* 35* 36* 37* 38* 39*
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Core 5: 40* 41* 42* 43* 44* 45* 46* 47*
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$ lparstat -E
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Failed to read /sys/devices/system/cpu/cpu0/spurr
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The message is complaining about CPU0 but the real issue is that in
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parse_sysfs_values() the test cpu_sysfs_fds[i].spurr >= 0 is valid even if
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the entry has not been initialized (cpu_sysfs_fds is alloc cleared). So
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if the number of threads online seen in assign_cpu_sysfs_fds is lower than
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threads_in_system, the loop in parse_sysfs_values() will read uninitialized
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entry, where .cpu=0.
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To prevent that, unset entries in the cpu_sysfs_fds should have the spurr
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fd set to -1.
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Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
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Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
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diff --git a/src/lparstat.c b/src/lparstat.c
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index a9e7bce..d2fdb3f 100644
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--- a/src/lparstat.c
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+++ b/src/lparstat.c
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@@ -163,6 +163,10 @@ static int assign_cpu_sysfs_fds(int threads_in_system)
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cpu_idx++;
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}
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+ /* Mark extra slots for offline threads unset, see parse_sysfs_values */
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+ for (; cpu_idx < threads_in_system; cpu_idx++)
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+ cpu_sysfs_fds[cpu_idx].spurr = -1;
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+
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return 0;
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error:
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fprintf(stderr, "Failed to open %s: %s\n",
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