[Ksummit-2008-discuss] DTrace

Grant Grundler grundler at google.com
Fri Jun 27 10:14:33 PDT 2008

On Fri, Jun 27, 2008 at 9:26 AM, Greg KH <greg at kroah.com> wrote:
> On Fri, Jun 27, 2008 at 09:50:18AM -0600, Matthew Wilcox wrote:
>> The ability to trace userspace programs is the key one for the postgres
>> people.  They get reports saying how long queries took to execute, which
>> tables were accessed, how long locks (postgres locks, that is, not
>> kernel ones) were held, cache hits, cache misses, etc.  It's _really_
>> useful for Postgres developers and admins.  And they only get it on
>> Solaris and MacOS, not Linux.
> Isn't this what oprofile on userspace programs is for?  Or am I totally
> mistaken here?

oprofile can sample how much time was spent in any given
function, but it doesn't deal with individual calls to those functions.
ie build a histogram of how long each call took and maybe what
the callgraph was. Think more like blocktrace or ktrace..


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