* Colin Fowler <[EMAIL PROTECTED]> wrote:
> These data may be much better for you. It's a single 15 second data
> collection run only when the actual ray-tracing is happening. These
> data do not therefore cover the data structure building phase.
>
> http://vangogh.cs.tcd.ie/fowler/cfs2/
hm, the system has considerable idle time left:
r b swpd free buff cache si so bi bo in cs us sy id wa
8 0 0 1201920 683840 1039100 0 0 3 2 27 46 1 0 99 0
2 0 0 1202168 683840 1039112 0 0 0 0 245 45339 80 2 17 0
2 0 0 1202168 683840 1039112 0 0 0 0 263 47349 84 3 14 0
2 0 0 1202300 683848 1039112 0 0 0 76 255 47057 84 3 13 0
and context-switches 45K times a second. Do you know what is going on
there? I thought ray-tracing is something that can be parallelized
pretty efficiently, without having to contend and schedule too much.
could you try to do a similar capture on 2.6.22 as well (under the same
phase of the same workload), as comparison?
there are a handful of 'scheduler feature bits' in
/proc/sys/kernel/sched_features:
enum {
SCHED_FEAT_NEW_FAIR_SLEEPERS = 1,
SCHED_FEAT_WAKEUP_PREEMPT = 2,
SCHED_FEAT_START_DEBIT = 4,
SCHED_FEAT_TREE_AVG = 8,
SCHED_FEAT_APPROX_AVG = 16,
};
const_debug unsigned int sysctl_sched_features =
SCHED_FEAT_NEW_FAIR_SLEEPERS * 1 |
SCHED_FEAT_WAKEUP_PREEMPT * 1 |
SCHED_FEAT_START_DEBIT * 1 |
SCHED_FEAT_TREE_AVG * 0 |
SCHED_FEAT_APPROX_AVG * 0;
[as of 2.6.24-rc7]
could you try to turn some of them off/on. In particular toggling
WAKEUP_PREEMPT might have an effect, and NEW_FAIR_SLEEPERS might have an
effect as well. (TREE_AVG and APPROX_AVG has probably little effect)
other debug-tunables you might want to look into are in the
/proc/sys/kernel/sched_domains hierarchy.
also, if you toggle:
/sys/devices/system/cpu/sched_mc_power_savings
does that change the results?
Ingo
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