oprofile for i586 kernels?
Dave Jones
davej at redhat.com
Sat Jun 24 05:55:31 UTC 2006
On Fri, Jun 23, 2006 at 10:29:45PM -0700, Jesse Barnes wrote:
> On Friday, June 23, 2006 8:24 pm, Dave Jones wrote:
> > oprofile needs P6 style MSRs, it doesn't make sense to enable it on
> > 586s. The performance monitoring counters were introduced with the
> > PPro for Intel & athlon for AMD. The other vendors never implemented
> > them (VIA still don't to this day even in their 686 flavoured C3s).
>
> Even for decent profiling support? I've used it in the past on my VIA
> EPIA based machine with some success, so I don't think it's completely
> useless, even if I'm not getting all the fancy performance counters.
> E.g.:
>
> samples % app name symbol name
> 2490 90.1847 vmlinux-2.6.16-rc5 acpi_processor_idle
> 69 2.4991 vmlinux-2.6.16-rc5 acpi_safe_halt
> 21 0.7606 bash (no symbols)
> 21 0.7606 vmlinux-2.6.16-rc5 do_wp_page
> 14 0.5071 oprofiled (no symbols)
> 13 0.4708 vmlinux-2.6.16-rc5 get_page_from_freelist
> 12 0.4346 ext3 (no symbols)
> 11 0.3984 libc-2.4.so
> __gconv_transform_utf8_internal
> 11 0.3984 libc-2.4.so mbrtowc
> 6 0.2173 libc-2.4.so _int_malloc
>
> is much better than the output I'd get from 'readprofile' after booting
> with builtin support, don't you think?
It's small enough, I guess turning it on isn't that big a deal.
Dave
--
http://www.codemonkey.org.uk
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