Re: [9fans] syscall spikes

[Devon H. O'Dell]

2007/4/17, Devon H. O'Dell <[EMAIL PROTECTED]>:

2007/4/17, Uriel <[EMAIL PROTECTED]>:
> fossil

I attempted to tprof fossil and I don't get any useful output. I even did:

for (i in `{ps a | grep fossil | awk '{ print $2 }'})
    echo profile > /proc/$i/ctl

[wait a while for spike]

for (i in `{ps a | grep fossil | awk '{ print $2 }'}) {
    echo $i
    tprof $i
}

All I get is a bunch of lines saying ``total: 0''.

What'm I missing? :(

I found the [undocumented] startsyscall argument to the process ctl
file, but I cannot get it to work. If I echo startsyscall >
/proc/N/ctl, I get ``echo: write error: bad process or channel control
request''.

What gives?

--dho

--dho

> On 4/17/07, Devon H. O'Dell <[EMAIL PROTECTED]> wrote:
> > Hi,
> >
> > I've been having syscall spikes. It's really weird. There will be
> > >40,000 in 1 second, (according to stats(8)) and it appears at a
> > fairly regular interval. I've tried running kprof, but I'm not sure
> > that it's running a global profile. Namely, when I come out of it, I
> > have tons of time spent in ``halt'', with very, very few (<100)
> > syscalls. Any ideas what I can do to find the culprit? It's gapping
> > sound playback, which is really annoying.
> >
> > --dho
> >
>