Re: [patch v3 0/8] sched: use runnable avg in load balance

From: Alex Shi
Date: Tue Apr 02 2013 - 22:57:42 EST


On 04/03/2013 10:46 AM, Michael Wang wrote:
> | 15 GB | 16 | 45110 | | 48091 |
> | 15 GB | 24 | 41415 | | 47415 |
> | 15 GB | 32 | 35988 | | 45749 | +27.12%
>
> Very nice improvement, I'd like to test it with the wake-affine throttle
> patch later, let's see what will happen ;-)
>
> Any idea on why the last one caused the regression?

you can change the burst threshold: sysctl_sched_migration_cost, to see
what's happen with different value. create a similar knob and tune it.
+
+ if (cpu_rq(this_cpu)->avg_idle < sysctl_sched_migration_cost)
+ burst_this = 1;
+ if (cpu_rq(prev_cpu)->avg_idle < sysctl_sched_migration_cost)
+ burst_prev = 1;
+


BTW, what's the job thread behaviour of pgbench, guess it has lots of
wakeup. what's the work and sleep ratio of pgbench?
--
Thanks Alex
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