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Re: MAXACTION exceeded error while using systemtap


On Wed, 2005-12-07 at 10:21 -0500, William Cohen wrote:
> Badari Pulavarty wrote:
> > On Tue, 2005-12-06 at 11:59 -0500, Frank Ch. Eigler wrote:
> > 
> >>Badari Pulavarty <pbadari@us.ibm.com> writes:
> >>
> >>
> >>>I am trying to collect pagecache usage info using systemtap
> >>>and I get following error, while reporting. What should I 
> >>>do fix it ?
> >>>[...]
> >>>ERROR: MAXACTION exceeded near embedded-code
> >>>at /usr/local/share/systemtap/tapset/logging.stp:9:29
> >>
> >>See http://sourceware.org/bugzilla/show_bug.cgi?id=1866
> > 
> > 
> > Okay, Thank you.
> > 
> > BTW, I am impressed with the NO (noticeable) overhead added 
> > by having systemtap probes. Of course, I wasn't really doing
> > a performance measurement. I was doing untars, kernel compiles
> > with probes in add_to_page_cache() and remove_from_page() -
> > which gets called a lot and didn't make much difference in the
> > kernel compile time :)
> > 
> > 
> > time with probe:
> > (Totals PageAdd = 215326 PageDel = 17612)
> > 
> > real    3m40.492s
> > user    5m44.894s
> > sys     1m2.276s
> > 
> > time without probe:
> > 
> > real    3m40.085s
> > user    5m45.650s
> > sys     1m1.572s
> > 
> > 
> > 
> > 
> > Thanks,
> > Badari
> > 
> 
> Assuming there is one probe fired per PageAdd and PageDel, there would 
> be 232,938 probes fired during the experiment's 220 seconds. This would 
> average 1059 probes per second. If one assumes about 1 microsecond 
> overhead per probe (rough guestimage) that would be about .23 seconds 
> over the run, pretty small.

Above data is not quite correct. The probe was collecting data for
untar & kernel compile. Time was reported only for kernel compile..

So, I collected that again, just for kernel compile:

Totals PageAdd = 151774 PageDel = 17495 
	(total = 169269 probes fired)

real    3m39.122s
user    5m44.446s
sys     1m1.976s


Thanks,
Badari


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