Re: [CFT][RFC] HT scheduler

[Nick Piggin <piggin@cyberone.com.au>]

Nick Piggin wrote:

>
> Don't ask me why it runs out of steam at 150 rooms. hackbench does
> something similar. I think it might be due to some resource running
> short, or a scalability problem somewhere else.


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%