BFS vs. mainline scheduler benchmarks and measurements

Posted Sep 8, 2009 12:30 UTC (Tue) by i3839 (guest, #31386)
In reply to: BFS vs. mainline scheduler benchmarks and measurements by mingo
Parent article: BFS vs. mainline scheduler benchmarks and measurements

Weird, I don't see /proc/sys/kernel/sched_latency_ns. After reading
the code it's clear it depends on CONFIG_SCHED_DEBUG, any reason for
that? It has nothing to do with debugging and the code saved is minimal.

to post comments

BFS vs. mainline scheduler benchmarks and measurements

Posted Sep 8, 2009 12:37 UTC (Tue) by mingo (subscriber, #31122) [Link] (5 responses)

Please send a patch, i think we could make it generally available - and also the other granularity options i think. CONFIG_SCHED_DEBUG default to y and most distros enable it. (alongside CONFIG_LATENCYTOP)

BFS vs. mainline scheduler benchmarks and measurements

Posted Sep 9, 2009 8:42 UTC (Wed) by realnc (guest, #60393) [Link] (1 responses)

I've tried those tweaks. They don't really help much.

BFS vs. mainline scheduler benchmarks and measurements

Posted Sep 10, 2009 9:53 UTC (Thu) by mingo (subscriber, #31122) [Link]

Thanks for testing it. It would be helpful (to keep reply latency low ;-) to move this to email and Cc: lkml.

You can test the latest upstream scheduler development tree via:

http://people.redhat.com/mingo/tip.git/README

BFS vs. mainline scheduler benchmarks and measurements

Posted Sep 9, 2009 11:50 UTC (Wed) by nix (subscriber, #2304) [Link] (1 responses)

I thought CONFIG_LATENCYTOP had horrible effects on the task_struct size and people were being encouraged to *disable* it as a result?

BFS vs. mainline scheduler benchmarks and measurements

Posted Sep 10, 2009 9:56 UTC (Thu) by mingo (subscriber, #31122) [Link]

It shouldnt have too big cost unless you are really RAM constrained. (read running: a 32 MB system or so) So it's a nice tool if you want to see a general categorization of latency sources in your system.

latencytop is certainly useful enough so that several distributions enable it by default. It has size impact on task struct but otherwise the runtime cost should be near zero.

BFS vs. mainline scheduler benchmarks and measurements

Posted Sep 10, 2009 19:35 UTC (Thu) by i3839 (guest, #31386) [Link]

I'll try to send a patch against tip later this week, not feeling too well at the moment.