Re: [CFT][RFC] HT scheduler

Nick Piggin
2003-12-11T13:09:14Z

William Lee Irwin III wrote:

>On Thu, Dec 11, 2003 at 07:57:31PM +1100, Nick Piggin wrote:
>
>>OK, it is spinning on .text.lock.futex. The following results are
>>top 10 profiles from a 120 rooms run and a 150 rooms run. The 150
>>room run managed only 24.8% the throughput of the 120 room run.
>>Might this be a JVM problem?
>>I'm using Sun Java HotSpot(TM) Server VM (build 1.4.2_01-b06, mixed mode)
>> ROOMS 120 150
>>PROFILES
>>total 100.0% 100.0%
>>default_idle 81.0% 66.8%
>>.text.lock.rwsem 4.6% 1.3%
>>schedule 1.9% 1.4%
>>.text.lock.futex 1.5% 19.1%
>>__wake_up 1.1% 1.3%
>>futex_wait 0.7% 2.8%
>>futex_wake 0.7% 0.5%
>>.text.lock.dev 0.6% 0.2%
>>rwsem_down_read_failed 0.5%
>>unqueue_me 3.2%
>>
>
>If this thing is heavily threaded, it could be mm->page_table_lock.
>

I'm not sure how threaded it is, probably very. Would inline spinlocks
help show up mm->page_table_lock?

It really looks like .text.lock.futex though, doesn't it? Would that be
the hashed futex locks? I wonder why it suddenly goes downhill past about
140 rooms though.