Messages in this thread | | | Date | Tue, 23 Dec 2003 21:13:55 +1100 | From | Nick Piggin <> | Subject | Re: [PATCH] 2.6.0 batch scheduling, HT aware |
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Nakajima, Jun wrote:
>BTW, Nick, does your SMT scheduler have "idle package prioritization" >which chooses an idle logical processor with the other local processor >idle if any (rather than just an idle processor with other local >processor running at full speed), when the scheduler requires an idle >local processor? That would prevent situations like two logical >processors run at full speed in the same processor package, with the >other processor package(s) idle in a same processor package(s). I >haven't reviewed your latest patch closely, and that is the one of the >things I want to do during the holidays. >
Yep, sched_balance_wake wakes to idle siblings if your domain has SD_FLAG_WAKE and idle_balance tries pulling tasks from any domain with SD_FLAG_NEWIDLE set if we're just about to become idle.
> >One question. Why did you remove SD_FLAG_IDLE flag from cpu_domain >initialization in the w27 patch? We've been seeing some performance >degradation with w27, compared to w26. >
I reworked things to not require this hopefully. w26 was quite broken with respect to the active balancing stuff. One thing I did in w27 was accidently release the code with cache_hot_time for the SMT domain set to 1ms instead of 0 in w26, so SD_FLAG_NEWIDLE is sometimes not allowed to pull a ready-to-run task off a sibling...
I haven't been able to do a great deal of performance tuning though, there is probably quite a bit of room for improvement.
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