[Crash-utility] Questions on multi-thread for crash

[David Wysochanski]

On Wed, Feb 22, 2023 at 1:57 AM Tao Liu <ltao at redhat.com> wrote:
>
> Hi David,
>
>
> On Tue, Feb 21, 2023 at 4:14 AM David Wysochanski <dwysocha at redhat.com> wrote:
> >
> > On Tue, Feb 7, 2023 at 11:34 PM Tao Liu <ltao at redhat.com> wrote:
> > >
> > > Hello,
> > >
> > > Recently I made an attempt to introduce a thread pool for crash utility, to
> > > optimize the performance of crash.
> > >
> > > One obvious point which can benefit from multi-threading is memory.c:vm_init().
> > > There are hundreds of MEMBER_OFFSET_INIT() related symbol resolving functions,
> > > and most of the symbols are independent from each other, by careful arrangement,
> > > they can be invoked parallelly. By doing so, we can shorten the waiting time of
> > > crash starting.
> > >
> > I realize this isn't the area of the code you mention, but did you consider
> > using the thread pool to speed up really slow commands such as 'search'?
> >
> Great suggestion! It is an interesting topic, I think I can take a try on it.
>
Fantastic, thanks Tao!

> > A while back I was taking some actual data in our production vmcore system
> > for 'slow' commands (I mean commands that engineers would have running
> > for hours/days and/or even fire up multiple crash instances to run them).  I
> > cannot recall all of the commands but 'search' was definitely on the top of
> > the list.
>
> Could you please provide a vmcore which takes crash hours/days for
> analysis, or steps I can reproduce it? Then I can debug and have a
> comparison of how much the performance can be improved by
> multi-threading.
>
Yes I'm sure either myself or someone else can provide at least one.
I'll do a little bit of digging then follow up with an email to you off-list
about it.

> Thanks,
> Tao Liu
>
> >
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