lkml.org 
[lkml]   [2020]   [Apr]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: What should we be doing to stress-test kfree_rcu()?
On Wed, Apr 01, 2020 at 04:50:12PM -0400, Joel Fernandes wrote:
> On Wed, Apr 01, 2020 at 11:44:15AM -0700, Paul E. McKenney wrote:
> > Hello!
> >
> > What should we be doing to stress-test kfree_rcu(), including its ability
> > to cope with OOM conditions? Yes, rcuperf runs are nice, but they are not
> > currently doing much more than testing base functionality, performance,
> > and scalability.
>
> I already stress kfree_rcu() with rcuperf right now to a point of OOM and
> make sure it does not OOM. The way I do this is set my VM to low memory (like
> 512MB) and then flood kfree_rcu()s. After the shrinker changes, I don't see
> OOM with my current rcuperf settings.
>
> Not saying that my testing is sufficient, just saying this is what I do. It
> would be good to get a real workload to trigger lot of kfree_rcu() activity
> as well especially on low memory systems. Any ideas on that?
>
> One idea could be to trigger memory pressure from unrelated allocations (such
> as userspace memory hogs), and see how it perform with memory-pressure. For
> one, the shrinker should trigger in such situations to force the queue into
> waiting for a GP in such situations instead of batching too much.
>
> We are also missing vmalloc() tests. I remember Vlad had some clever vmalloc
> tests around for his great vmalloc rewrites :). Vlad, any thoughts on getting
> to stress kvfree_rcu()?
>
Actually i updated(localy for my tests) the lib/test_vmalloc.c module with extra
test cases to stress kvfree_rcu() stuff. I think i should add them :)

--
Vlad Rezki

\
 
 \ /
  Last update: 2020-04-01 23:17    [W:0.050 / U:0.908 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site