On Thu, 6 Apr 2006, Sven Petai wrote:

On Wednesday 05 April 2006 21:52, Mike Silbersack wrote:

If you're willing to spend more time looking at this, I suggest that you
run truss or ktrace on the super-smack processes.  I did a small amount of
mysql vs postgres vs firebird benchmarking two years ago for a class
project, and noticed that mysql's results were showing the same phenomena
- our test program was using more cpu than mysqld.  I run truss on our
test program and found that it was doing ONE BYTE READS from the socket,
rather than something larger.

I never had the time to see if the problem was fixed at a later time or
not.  You may wish to see if that same condition is still happening.

here are ktrace results for supersmack and mysqld from a dualcore opteron box
running select smack with 100 threads and 10000 queries
os: fbsd 6.1 prerelease

==== syscall stats for supersmack ====

request sizes for syscall read
 size  count   %
---------------------------
  4    15489977  47.06%
  50    3982797  12.10%
  1    3873493  11.77%
  52    2654645  8.07%
  60    1937753  5.89%
  5    1933249  5.87%
  8192    1931176  5.87%
  53    790179  2.40%
  51    274285  0.83%

<rest of info cut>

Thanks for running those tests, Sven. It looks like the problem still exists. :(

I wish I had time to work on this...

Mike "Silby" Silbersack
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