Messages in this thread | | | From | Andrew Theurer <> | Subject | HT and idle = poll | Date | Wed, 5 Mar 2003 23:18:04 -0600 |
| |
The test: kernbench (average of kernel compiles5) with -j2 on a 2 physical/4 logical P4 system. This is on 2.5.64-HTschedB3:
idle != poll: Elapsed: 136.692s User: 249.846s System: 30.596s CPU: 204.8% idle = poll: Elapsed: 161.868s User: 295.738s System: 32.966s CPU: 202.6%
A 15.5% increase in compile times.
So, don't use idle=poll with HT when you know your workload has idle time! I have not tried oprofile, but it stands to reason that this would be a problem. There's no point in using idle=poll with oprofile and HT anyway, as the cpu utilization is totally wrong with HT to begin with (more on that later).
Presumably a logical cpu polling while idle uses too many cpu resources unnecessarily and significantly affects the performance of its sibling.
-Andrew Theurer
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |