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From Dan Kegel <d...@alumni.caltech.edu>
Subject re: Linux and Apache performance, Update
Date Thu, 03 Jun 1999 16:55:33 GMT
Juergen,
thanks for keeping us informed!

First:
I saw one possible problem straight off:
you compiled Apache with 
  -D USE_FCNTL_SERIALIZED_ACCEPT 
To get the benefit of the wake-one kernel patches,
you have to compile instead with
  -DSINGLE_LISTEN_UNSERIALIZED_ACCEPT

As far as I know, the way you compiled Apache, 
the kernel is still waking up all processes
("the thundering herd") when it should only
be waking up one.  This hurts SMP performance.

Please have a look at the section "Suggestions
for future benchmarks" in 
http://www.kegel.com/mindcraft_redux.html

Second: I see your load generating program uses
multiple processes, and you mention that it can't
generate enough load to really hit an SMP server hard.
Perhaps you should try a different load client, e.g. 
http://www.acme.com/software/http_load/  It
might be able to load your server down more effectively.

Thanks,
Dan

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