lkml.org 
[lkml]   [2008]   [Sep]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: unpredictability in scheduler test results -- still present
Ingo Molnar wrote:
> * Chris Friesen <cfriesen@nortel.com> wrote:

>> It turns out that disabling CONFIG_DYNAMIC_FTRACE makes the load
>> balancing problem go away and causes all cpus to be used.
>>
>> With this option enabled, the problem seems to be present as far back
>> as 2.6.27-rc2. (2.6.27-rc1 doesn't compile on my machine, and 2.6.26
>> doesn't have ftrace).
>>
>> I have no idea why turning on dynamic ftrace would affect load
>> balancing behaviour, but it's very repeatable. The very first test
>> run after booting works fine, and all successive runs fail to balance
>> properly.

> OTOH, what does 'truning on dftrace' exactly mean? Just enabling it in
> the .config, or also activating it via /debug/tracing/current_tracer?

Just enabling it in the .config is enough to trigger the behaviour
change. I'm not explicitly activating any traces.

Chris


\
 
 \ /
  Last update: 2008-09-29 17:47    [W:0.063 / U:1.352 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site