The sixty second pmc howto

[Andrew Gallatin]

Robert Watson writes:

 > (2) Run "pmcstat -S instructions -O /tmp/sample.out" to start sampling of
 >      instruction retirement events, saving the results to /tmp/sample.out.

Dumb question, but what does "instructions" really mean?  The number
of instructions, the time spent executing them, ?

<.....>

 > Since there is no call graph information in the sample, the first few pages of 
 > gprof output will be of limited utility, but the summary table by function is 
 > the bit I found most useful:

You can use gprof -l to suppress the printing of the call-graph profile

My only problem with hwpmc is that it will not work for kernel
modules.  I wonder if somebody with enough toolchain fu could take
kldstat output and produce a pre-linked elf executable image
containing kernel+modules which could be used for hwpmc, and also for
crash dump analysis.  Or is there another, better, way to get a 
complete symbol table of the kernel & all kernel modules?

 > So if you're doing kernel performance work, and not already using pmc, you 
 > probably should be.

Very much agreed.

Drew