[oi-dev] Running a debug kernel

[Michael Schuster]

Liam,

I'd look at this from a more generic POV (that's all I can do ATM, I'm
afraid):

In order for a debug kernel to be useful, it has to record (you guessed it)
debug information (in addition to what the kernel records without debug -
obviously). This additional recording effort will consume space and CPU
cycles. How much is consumed depends on what you're doing and what kind of
debug information is recorded.

The impact will depend on how much you're doing - if your system is only
lightly loaded, the additional load may go unnoticed.

So, to get the answer for your specific circumstances, I'd first run your
usual job(s)/workloads/whatever using the debug kernel, and record the
times various tasks consume. Then repeat the exercise with a non-debug
kernel, and compare times. This will give you an idea about *your*
situation.

HTH
Michael


On Thu, Jul 10, 2014 at 7:05 AM, Liam Slusser <lslusser at gmail.com> wrote:

> Scott -
>
> Oh wow, thank you so much for the reply.  I'll run on the debug kernel for
> a few days to make sure it is stable and then rebuild with no debug.
>
> thanks,
> liam
>
>
>
> On Wed, Jul 9, 2014 at 9:59 PM, Scott McClung <scott at mcclung.com> wrote:
>
>> * Liam Slusser (lslusser at gmail.com) [140709 05:55]:
>> > Does running a debug kernel cause a performance impact?  Basically I
>> build
>> > a nightly image with debugging enabled (defaults) and all seems to work
>> > great but I'm wondering if there is a performance penalty and I should
>> > rebuild without debugging?
>>
>> I am not an OI developer, but I had reason to build my own
>> illumos-gate a few months ago for testing a patch I thought might help
>> my particular workload.  I found that the debug build was much slower,
>> on the order of 1/5th the I/O performance of a non-debug build for our
>> iozone benchmarks.
>>
>> --
>> Scott McClung (scott at mcclung.com)
>>
>> _______________________________________________
>> oi-dev mailing list
>> oi-dev at openindiana.org
>> http://openindiana.org/mailman/listinfo/oi-dev
>>
>
>
> _______________________________________________
> oi-dev mailing list
> oi-dev at openindiana.org
> http://openindiana.org/mailman/listinfo/oi-dev
>



-- 
Michael Schuster
http://recursiveramblings.wordpress.com/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://openindiana.org/pipermail/oi-dev/attachments/20140710/ef28953b/attachment-0005.html>