Re: Fwd: Systemtap support for disk i/o per pid

[Li Guanglei <guanglei at cn dot ibm dot com>]

Nguyen, Thang P ??:
> As for disk I/O, currently I am also adding more hooks into ioscheduler
> tapset to track disk activities such as block I/O location and estimate
> disk seek time.  Li, I can send you what I have, and see where to fit
> (or perhaps consolidate) them if necessary.

Great. I read your codes, it looks good but I have one comment. I 
think ioscheduler may not be a suitable category for submit_bio and 
other alias definitions like disk activities. I think we should define 
new stap files and alias categories for these probes. Do you think so?

I also copied this mail to Jose Santos since he is also the one doing 
LKET work with me.

- Guanglei

> Thang
>
> -----Original Message-----
> From: systemtap-owner@sourceware.org
> [mailto:systemtap-owner@sourceware.org] On Behalf Of Li Guanglei
> Sent: Sunday, May 28, 2006 11:39 PM
> To: James Dickens
> Cc: systemtap@sourceware.org
> Subject: Re: Fwd: Systemtap support for disk i/o per pid
>
> James Dickens ??:
> > resending due to improper mime type on the original
> >
> > it would be simpler in most cases to probe syscalls that are easily
> > trackable to pid's though this won't give a totally accurate of IO
> > because of caching, but it is the easiest, and safest. When you go to
> > lower level kernel interfaces it becomes difficult to attiribute
> > actions with the pid that caused them.
> >
> > James Dickens
> > uadmin.blogspot.com
>
> Currently Systemtap could make you able to trace all syscalls by pid,
> e.g:
>    stap -e "probe addevent.syscall {} " -x pid
> to trace both entry & return of all syscalls
> or:
>    stap -e "probe addevent.syscall {}" -c command
>
> I am getting started with Jose to implement new hooks about IO system 
> calls which could give more details other than the syscall name. And 
> we are also trying to map systemcall to the io scheduler and scsi hooks.
>
> - Li Guanglei