Date: Fri, 14 Jan 2011 22:10:23 -0800 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: George Neville-Neil <gnn@freebsd.org> Cc: freebsd-current@freebsd.org, Ryan Stone <rysto32@gmail.com> Subject: Re: Profiling code execution on amd64? Message-ID: <20110115061023.GA41547@troutmask.apl.washington.edu> In-Reply-To: <1D4725BB-0A0A-44FB-9FF1-23969C469AA6@freebsd.org> References: <20110113171139.GA32250@troutmask.apl.washington.edu> <AANLkTi=C4L9fn7q8PfJgY=8c24BQnZTC9s7BubsrUYxv@mail.gmail.com> <20110114040549.GA36430@troutmask.apl.washington.edu> <1D4725BB-0A0A-44FB-9FF1-23969C469AA6@freebsd.org>
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On Fri, Jan 14, 2011 at 03:40:46PM -0500, George Neville-Neil wrote: > > 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: > >> > >> # kldload hwpmc > >> # pmcstat -S unhalted-cycles -O /tmp/samples.out ../penetration > >> # pmcstat -R /tmp/samples.out -G /tmp/penetration.txt > >> > >> > >> 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. > > > > > > Thanks. I'll give it a try, but my initial attempt seems to > > indicate that one needs to be root to use hwpmc. > > > > 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 > > > > 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 > Thanks. I'll look at the tutorial. Meanwhile, should gprof be removed from the base system because it appears broken? -- Steve
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