Forum OpenACS Development: Re: OpenACS Performance Tests

Posted by Gustaf Neumann on
The primary question is to figure out, what resources are running out. Candidates
  - cpu
  - amount of memory
  - memory bandwidth
  - i/o

and who is causing it
  - aolserver (e.g. lock-contention)
  - postgres (e.g. checkpoint handling, vacuuming, 
    some complex queries...)

is the whole machine in a bad state (e.g. 
load etc. how does it react on the console)
or just the aolserver or the database?

how many cpus do you have on your system 
(fgrep processor /proc/cpuinfo)?

In respone to your questions:
 - i have never seen thread destroy as a 
   performance problem, but under "normal
   conditions", not all threads end 
   at more or less the same time.
   Normally, the problem with the thread
   destroys is just that they might be
   created quite soon later, thread 
   creation is slow, when the blueprint
   is large (when you have many packages
   installed). However, if one has a large
   blueprint, the thread cleanup has to 
   free all of the contents, which 
   might be a couple of million individual
   free operations. This might entail 
   as well quite a large number of 
   memory locks.

 - there are as well many reasons
   for possible waiting operations.
   Do you see error message concerning
   DEADLOCKS in you database? OpenACS
   5.4 uses less locks (which were introduced
   to overcome some problems in PostgreSQL
   8.0 and 8.1).

-gustaf neumann