Messages in this thread | | | Date | Tue, 16 May 2006 15:51:35 +0200 | From | Andreas Mohr <> | Subject | Re: [patch 00/14] remap_file_pages protection support |
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Hi,
On Tue, May 16, 2006 at 11:30:32PM +1000, Nick Piggin wrote: > I also tried running kbuild under UML, and could not make find_vma take > much time either [in this case, the per-thread vma cache patch roughly > doubles the number of hits, from about 15%->30% (in the host)]. > > So I guess it's time to go back into my hole. If anyone does come across > a find_vma constrained workload (especially with threads), I'd be very > interested.
I cannot offer much other than some random confirmation that from my own oprofiling, whatever I did (often running a load test script consisting of launching 30 big apps at the same time), find_vma basically always showed up very prominently in the list of vmlinux-based code (always ranking within the top 4 or 5 kernel hotspots, such as timer interrupts, ACPI idle I/O etc.pp.). call-tracing showed it originating from mmap syscalls etc., and AFAIR quite some find_vma activity from oprofile itself. Profiling done on 512MB UP Athlon and P3/700, 2.6.16ish, current Debian. Sorry for the foggy report, I don't have those logs here right now.
So yes, improving that part should help in general, but I cannot quite say that my machines are "constrained" by it.
But you probably knew that already, otherwise you wouldn't have poked in there... ;)
Andreas Mohr - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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