[concurrency-interest] Some interesting (confusing?) benchmark results

Stanimir Simeonoff stanimir at riflexo.com
Wed Feb 13 05:45:25 EST 2013


> Is there a way to know how many physical processors are available on the
> JVM?
>
> On linux you can use taskset -p <pid>
(pid you can retrieve form /proc/self )
and you can use /proc/cpuinfo to determine which processors have siblings.

Quite inconvenient overall. So kernels might have /proc/self/affinity which
would make life easier .
And of course there is JNI and syscall.

Stanimir



> Cheers,
>>
>
>>
>>
>> Nathan Reynolds<http://psr.us.oracle.com/wiki/index.php/User:Nathan_Reynolds>| Architect |
>> 602.333.9091
>> Oracle PSR Engineering <http://psr.us.oracle.com/> | Server Technology
>>  On 2/12/2013 2:18 PM, √iktor Ҡlang wrote:
>>
>>
>>
>>
>> On Tue, Feb 12, 2013 at 8:28 PM, Kirk Pepperdine <kirk at kodewerk.com>wrote:
>>
>>> >
>>> > Do you agree that thread pool sizing depends on type of work? (IO
>>> bound vs CPU bound, bursty vs steady etc etc)
>>>  Yes
>>> > Do you agree that a JVM Thread is not a unit of parallelism?
>>>  Yes
>>> > Do you agree that having more JVM Threads than hardware threads is bad
>>> for CPU-bound workloads?
>>>  No, even with CPU bound workloads I have found that the hardware/OS is
>>> much better at managing many workloads across many threads than I am. So a
>>> few more threads is ok, many more threads is bad fast.
>>>
>>
>>  That's an interesting observation. Have any more data on that? (really
>> interested)
>> As I said earlier, for CPU-bound workloads we've seen the best
>> performance when only loading 60-70% of the cores (other threads exist on
>> the machine of course).
>>
>>  Cheers,
>>
>>>>
>>
>>>
>>> Regards,
>>> Kirk
>>
>>
>>
>>
>>  --
>> *Viktor Klang*
>> *Director of Engineering*
>> *
>> *
>> Typesafe <http://www.typesafe.com/> - The software stack for
>> applications that scale
>> Twitter: @viktorklang
>>
>>
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>
>
> --
> *Viktor Klang*
> *Director of Engineering*
> *
> *
> Typesafe <http://www.typesafe.com/> - The software stack for applications
> that scale
> Twitter: @viktorklang
>
> _______________________________________________
> Concurrency-interest mailing list
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> http://cs.oswego.edu/mailman/listinfo/concurrency-interest
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>
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