Re: [PATCH] Add kallsyms_lookup() result cache

[Jesse Barnes <jbarnes@engr.sgi.com>]

On Tuesday, June 22, 2004 3:45 pm, Brent Casavant wrote:
> On Sat, 19 Jun 2004, Albert Cahalan wrote:
> > I'm not so sure anything needs to be fixed, save for SGI upgrading
> > to a more modern procps. There are many more important things:
>
> OK, I looked into this more closely, and gave procps 3.2.1 a spin.
> This gives us a similar speedup (top now only consumes 60% of a CPU)
> to that which I obtained by cacheing symbol lookups and using an old
> procps.  This difference is certainly explainable by top now only
> obtaining wchan information for displayed processes.
>
> 60% is far better than 800%, so this is certainly progress.  However
> 60% is also still quite a bit of CPU time.  I'll spend some cycles
> trying to whittle it down some more, but I'm not all that hopeful.

Is the 60% mainly kernel or user time now?  There were some good ideas in this 
thread that we could use to speed up symbol table searching.  And if opening 
and reading /proc/kallsyms is taking a significant portion of the time, we 
could probably trim it down too by only reading it once and polling for 
module insertion/removal.

Jesse