Re: Threaded execution (was: Interesting Bugs in 12cR1)
- From: Frits Hoogland <frits.hoogland@xxxxxxxxx>
- To: Niall Litchfield <niall.litchfield@xxxxxxxxx>
- Date: Fri, 12 Jul 2013 20:33:59 +0200
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On a VM, it's needed to use an alternative for native cpu timing (-e =
cpu-clock), but you've done that, otherwise you would see nothing.
What is your kernel version? A quick peek on the internet shows it seems =
to be a clock-source problem with older kernel versions. I haven't seen =
this with 2.6.32+
Frits Hoogland
http://fritshoogland.wordpress.com
frits.hoogland@xxxxxxxxx
+31 6 53569942
On Jul 12, 2013, at 8:08 PM, Niall Litchfield =
<niall.litchfield@xxxxxxxxx> wrote:
>=20
> On Jul 12, 2013 6:28 PM, "Frits Hoogland" <frits.hoogland@xxxxxxxxx> =
wrote:
> >
> > It depends on where the time is spend. Use perf top or record to
> > measure functions for threaded and non threaded performance.
>=20
> I'm so glad you said that :). Consistently when I do this (on a vm) =
the greatest single sample count is for acpi_pm_read. There's no good =
explanation I've found for this. I have some ideas but 30% of samples in =
this call compared with <5% in the various qer* Oracle function calls =
seems wrong in a swingbench test. I suspect I'm missing the idiots guide =
to perf/linux kernel functions..
>=20
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