[Zope] zserver-threads

Jake jake at zopezone.com
Tue Jan 31 15:53:13 EST 2006


Am I gleaming from that that you are proposing a less-is-more approach to
threads?

Here is what I have been using:
- Zope 2.7.8 (Plone 2.1.2)
- RH Linux
- AMD Athlon 64 3200+ 2.0 GHz
- 2GB DDR RAM
- 120,000 hits a day
- 392,036 objects in database
- 2 threads
- 100,000 object cache size

This seems to eat up about half of the RAM on the server.

Would one thread but double the cache size do better?

Jake
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On Tue, January 31, 2006 2:40 pm, Dieter Maurer said:
> Jens Vagelpohl wrote at 2006-1-31 15:07 +0000:
>>On 31 Jan 2006, at 15:01, Jake wrote:
>>
>>> http://plone.org/documentation/how-to/threads-vs-cache-size
>>
>>That article contains little information to back up the conclusions,
>>and some of it is patently wrong. Another case of hearsay and half-
>>thruths being propagated by well-meaning but uninformed parties.
>
> There is a convincing example (I think from Matt Kromer) what
> happens to "mean response time" when the number of threads
> is increased from 1 to 2:
>
>   Assume you have 2 units of work. If you have a single
>   thread, 1 unit is done, then the second. The
>   mean response time is (1 + 2) / 2 = 1.5.
>
>   Now assume you have two threads (but a single processor).
>   Both threads work (quasi) parallel but have only half of the
>   processor power. Both will take 2 time units to perform
>   their unit of work. The mean response time is (2 + 2) / 2 = 2.
>
> You get the same ratios whenever you double the number of threads
> (but keep the number of processors and all your work is CPU bound).
>
>
> Things become more difficult when you have a mix of very small
> requests and very long requests. You then may want a higher
> level of concurrency to not let the small requests being
> blocked by the long ones.
>
>
> --
> Dieter
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