[Xorp-hackers] PATCH: Enable libxipc tests
Bruce Simpson
bms at incunabulum.net
Thu Nov 26 14:04:33 PST 2009
Ben Greear wrote:
>
> Can you run perf tests with what you've checked in so far?
Thanks for doing this, this is the meat I need just now.
Not yet. I'm just about to merge your stuff for receiver/sender shortly.
I was up fairly late last night assessing tools.
It looks like 'mpatrol' is still king of the heap profilers. Valgrind
looked to have swallowed it; its error messages are very similar.
I found Google Performance Tools forces you to use their tcmalloc, which
probably doesn't yield correct results about the behaviour of the malloc
on a typical system. FreeBSD's jemalloc can generate ktrace records,
but this has syscall overhead.
The main reason I'm looking at heap profiling, is because Marko Zec, who
worked on XRL performance a few years ago, hinted strongly that
allocations were the source of XRL's slowness on the hot path BGP-RIB-FEA.
He didn't have conclusive figures, but the oprofile dump you posted
hints at that; the CPU's tied up in libstdc++, probably the allocator.
Re function profiling: I am getting around to those changes. At the
moment, Function Check (fnccheck) looks as though it is a bit stronger
than gprof, and KProf can digest output from both of them:
http://www.freshports.org/devel/fnccheck/
http://kprof.sourceforge.net/
If you have an AMD Linux box handy, AMD CodeAnalyzer looks like it's
worth a shot; it does all the ELF/DWARF lookup, graphing, cache and
cycle profiling, etc.
I have a spare amd64 lying around, if I can find time, I may try it
under Fedora (which seems to have better packaging for it).
DTrace is king of the non-invasive tap, but there is no pid provider
support in FreeBSD yet. All of the Sun examples for tracing userland
calls need the pid provider.
"The Malloc Wars" is worth a read, although not everything in there is fact:
http://www.makeitfly.co.uk/Presentations/malloc1.pdf
BTW: FreeBSD 8.0 is going to be dedicated to the memory of John Birrell,
who did the port; he passed away from a stroke on the 20th. At FUNIX
Tuesday, we toasted to him and DTrace.
>
> It's thanksgiving here, but might get a chance to poke at it
> early next week.
No turkey for us Limeys for another month...
cheers,
BMS
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