Re: LIO/sec per CPU limit? Is it Hardware or Oracle code?

Stefen,
If I didn't post the kernel, I should have

$uname -r
2.6.32-696.1.1.e16.x86_64

All I know about perf is that the fiber cards had driver issues with newer kernels which is what is preventing the installation of perf.

I'll take a look at some of your links.

Thanks for the pointers.

Henry

On Sep 5, 2017 5:15 AM, "Stefan Koehler" <contact_at_soocs.de> wrote:

> Hello Henry,
>
> > 1. Our sysadm said that there are kernel issues and "perf stat" cannot
> run on these systems
>
> I really would like to hear about these kernel issues and his concerns -
> never seen an issue with these.
>
>
> > Also RAPL throttling is on in the slow server. I am guessing this could
> account for the throttled cpu speed. I am starting to google search to see
> where this can be set from. Anyone out there know any good resources on
> RAPL throttling or how to disable it?
>
> Unfortunately you have not mentioned your linux kernel version yet (or i
> just missed it) but there are several ways to drill down into RAPL.
>
> 1) PowerCap interface: https://www.kernel.org/doc/
> Documentation/power/powercap/powercap.txt
> 2) Perf
> 3) MSR registers (/dev/msr)
>
> However if you can do the fancy stuff at all depends on BIOS (and vendor).
> If you run dmesg you may see some messages about "intel_rapl" to get an
> idea if it works anyway with your hardware.
>
> Best Regards
> Stefan Koehler
>
> Independent Oracle performance consultant and researcher
> Website: http://www.soocs.de
> Twitter: _at_OracleSK
>
> > Henry Poras <henry.poras_at_gmail.com> hat am 5. September 2017 um 06:39
> geschrieben:
> >
> > Figured it was time to send the list an update.
> > 1. Our sysadm said that there are kernel issues and "perf stat" cannot
> run on these systems
> > 2. I installed a slob instance on both a fast and slow server. There was
> no way to stop our workload from running, but I ran slob multiple times,
> trying to keep each run short (~3 minutes) so the underlying workload would
> not vary much. Also tried running when the load was relatively low. All of
> the run results were pretty consistent with one another. Configuring SLOB
> to run strictly LIO, I saw ~4M lio/sec vs. 1.5M lio/sec
> > 3. Our sysadm did get turbostat installed. What I take as the most
> important output from that was:
> > slow: TSC_MHz - 2600 Bzy_MHz - 1200 PKG_% - 100%
> > fast: TSC_MHz - 2606 Bzy_MHz - 3110 PKG_% - 0%
> >
> > So the clock speeds are nearly identical, ,but the running speeds when
> busy are very different. Also RAPL throttling is on in the slow server. I
> am guessing this could account for the throttled cpu speed. I am starting
> to google search to see where this can be set from. Anyone out there know
> any good resources on RAPL throttling or how to disable it?
> >
> > Thanks.
> >
> > Henry
>

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