Date: Fri, 14 Jan 2011 15:40:46 -0500 From: George Neville-Neil <gnn@freebsd.org> To: Steve Kargl <sgk@troutmask.apl.washington.edu> Cc: freebsd-current@freebsd.org, Ryan Stone <rysto32@gmail.com> Subject: Re: Profiling code execution on amd64? Message-ID: <1D4725BB-0A0A-44FB-9FF1-23969C469AA6@freebsd.org> In-Reply-To: <20110114040549.GA36430@troutmask.apl.washington.edu> References: <20110113171139.GA32250@troutmask.apl.washington.edu> <AANLkTi=C4L9fn7q8PfJgY=8c24BQnZTC9s7BubsrUYxv@mail.gmail.com> <20110114040549.GA36430@troutmask.apl.washington.edu>
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On Jan 13, 2011, at 23:05 , Steve Kargl wrote: > On Thu, Jan 13, 2011 at 10:08:30PM -0500, Ryan Stone wrote: >> I would suggest using hwpmc for profiling: >>=20 >> # kldload hwpmc >> # pmcstat -S unhalted-cycles -O /tmp/samples.out ../penetration >> # pmcstat -R /tmp/samples.out -G /tmp/penetration.txt >>=20 >>=20 >> You can also get pmcstat to generate gprof-compatible output with -g, >> but I never use the mode so I'm really not sure what it gives you. I >> think that you have to run gprof on the output or something, but = don't >> hold me to that. >=20 >=20 > Thanks. I'll give it a try, but my initial attempt seems to > indicate that one needs to be root to use hwpmc. =20 >=20 > laptop:kargl[210] pmcstat -S unhalted-cycles -O /tmp/samples.out = ../penetration > pmcstat: ERROR: Cannot allocate system-mode pmc with specification > "unhalted-cycles": Operation not permitted >=20 You only need to be root to profile the kernel or someone else's = process. This tutorial might help: www.dcbsdcon.org/speakers/slides/neville-neil_dcbsdcon2009.pdf Best, George
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