Messages in this thread | | | From | Bas van der Oest <> | Date | Wed, 25 Apr 2012 09:24:11 +0200 | Subject | Re: /proc/stat information incorrect |
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Thanks for your consideration Martin. > CONFIG_IRQ_TIME_ACCOUNTING comes to mind. Is this enabled for your > kernel ?
This configuration was not yet enabled. I tried this configuration with and without the patch you mentioned (git a25cac5198d4ff28). The results are still not completely as expected:
With patch, with CONFIG_IRQ_TIME_ACCOUNTING: user nice system idle iowait irq softirq sum cpu 5 0 373 7610 0 55 382 8425 cpu0 0 0 1 1042 0 18 1 1062 cpu1 0 0 1 1058 0 1 0 1060 cpu2 0 0 1 1060 0 0 0 1061 cpu3 0 0 0 1061 0 1 0 1062 cpu4 2 0 75 505 0 36 380 998 cpu5 1 0 82 983 0 0 0 1066 cpu6 1 0 139 911 0 0 0 1051 cpu7 1 0 74 988 0 0 0 1063
Revoked patch and CONFIG_IRQ_TIME_ACCOUNTING: user nice system idle iowait irq softirq sum cpu 8 0 461 7854 0 55 448 8826 cpu0 0 0 1 1056 0 15 1 1073 cpu1 0 0 1 1073 0 0 1 1075 cpu2 1 0 1 1073 0 0 0 1075 cpu3 0 0 1 1217 0 0 1 1219 cpu4 3 0 147 511 0 39 447 1147 cpu5 1 0 106 967 0 0 0 1074 cpu6 1 0 99 972 0 0 0 1072 cpu7 1 0 106 985 0 1 1 1094
Looking at the sum column still some unexpected behaviour is seen. The CONFIG_IRQ_TIME_ACCOUNTING seems to help but the interrupt handling CPU (CPU4) is still "lazy" when the original code is used (with patch). If the patch is revoked some other CPUs seem to spend more time than is really available. Both scenarios should not be possible imho.
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