[SR-Users] async workers

[Alex Balashov]

On 10/24/2014 09:07 AM, Daniel-Constantin Mierla wrote:
> Hello,
>
> On 23/10/14 03:36, Alex Balashov wrote:
>> Hi,
>>
>> What is the practical limit to the number of async worker processes?
>>
>> With SIP child processes, it seems to be about the number of available
>> CPUs in /proc/cpuinfo. After that--at least, per my testing--one
>> begins to hit the point of diminishing returns, presumably due to SHM
>> IPC and synchronisation issues.
>>
>> Is the restriction similar in the async execution context?
> no specific restriction. Also, I haven't seen any degradation when using
> more sip worker processes that cpus, which I do have always (at least 2
> per CPU), because a worker can do quite a lot of I/O.

I have seen such degradation, at least in my VM testing environment. I 
find that I get the highest CPS (e.g. with sipp) with the smallest 
number of workers.

Actually, I get as good throughput with 4 workers (in an 8 "CPU" 
scenario on a quad-core processor) as I do with 8! Increasing beyond 8 
leads to diminishing returns.

-- 
Alex Balashov - Principal
Evariste Systems LLC
Tel: +1-678-954-0670
Web: http://www.evaristesys.com/, http://www.alexbalashov.com/

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