Re: What is GetXid/FreeXid supposed to actually do?

On Sun, May 24, 2009 at 2:31 PM, Christoph Hellwig <[email protected]> wrote:
> On Sun, May 24, 2009 at 03:21:07PM -0400, Jeff Layton wrote:
>> Any objection to just replacing this xid value with the pid or tgid
>> instead? Does this xid value give you anything that that doesn't?
>
> Yeah, from all that I can see there is always at most one xid in
> use per thread.  So just replacing it with a tgid should work easily.
> Even better would be replacing all that ad-hoc debugging with the
> ftrace event tracer.

That may work (using the tgid) but there are various cases where it was
helpful to distinguish log entries this way (rather than simply using
timestamps,
especially since dmesg is lossy so you don't always see the function entry
and exits) when you have multiple requests in a series from one or more threads
request from thread1, request from thread 2, request 2 from thread1,
request 2 from thread 2 etc.

Using the ftrace event tracer may be good enough for some of this
(except the stats gathering, counters) - any pointers to its
use in NFS?




-- 
Thanks,

Steve