lkml.org 
[lkml]   [2022]   [Jan]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH] livepatch: Avoid CPU hogging with cond_resched
On Mon, Jan 10, 2022 at 8:17 AM Joe Lawrence <joe.lawrence@redhat.com> wrote:
>
> On 1/7/22 11:46 AM, Song Liu wrote:
> > On Fri, Jan 7, 2022 at 6:13 AM Joe Lawrence <joe.lawrence@redhat.com> wrote:
> >>
> >> On 12/29/21 4:56 PM, David Vernet wrote:
> >>> For example, under certain workloads, enabling a KLP patch with
> >>> many objects or functions may cause ksoftirqd to be starved, and thus for
> >>> interrupts to be backlogged and delayed.
> >>
> >> Just curious, approximately how many objects/functions does it take to
> >> hit this condition? While the livepatching kselftests are more about
> >> API and kernel correctness, this sounds like an interesting test case
> >> for some of the other (out of tree) test suites.
> >
> > Not many patched functions. We only do small fixes at the moment. In the recent
> > example, we hit the issue with ~10 patched functions. Another version
> > with 2 to 3
> > patched function seems fine.
> >
> > Yes, I think this is an important test case.
> >
>
> Thanks, Song. If you can share any test setup details, I'll pass those
> along to our internal QE group. And once merged, we'll be adding this
> one to the list of backports for our distro.

We get this on shadow production traffic of our web service, which we cannot
recreate out of our data centers.
I tried to use iperf to generate traffic (among a few hosts), but it
doesn't work.
At the moment, I am not sure what's the easiest way to repro this.

Thanks,
Song

\
 
 \ /
  Last update: 2022-01-11 02:50    [W:0.069 / U:0.484 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site