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Full Discussion: Help optimizing sort of large files
Top Forums UNIX for Advanced & Expert Users Help optimizing sort of large files Post 302925635 by Corona688 on Tuesday 18th of November 2014 10:50:31 AM
Old 11-18-2014
Quote:
Originally Posted by kogorman3
Size and number are linked. If they're bigger, there are fewer of them.
It doesn't work that way. It doesn't run 16384 individual merges simultaneously, then 4096 merges simultaneously, then 1024, etc etc. It always does the number you tell it to, as many times as it takes to process the list of things to do.

I don't think small sorts hurt you, especially since they're small enough to be cached. What hurts you are merges on too many files at once for the disk to seek between, reducing it's I/O throughput.

Remember you are trying to find a "sweet spot" where CPU use and disk throughput are both at peak -- where the system can sustain full disk and cpu use.

Quote:
True. I do not do anything to clear the caches before each run, but the tests are done by scripts that always do them in the same order, so I would expect more uniformity than I've seen so far.
Check if you're eating into swap sometimes. Hitting swap could have severe performance penalties that throw off your tests.
 

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LEARN ABOUT CENTOS

x11perfcomp

X11PERFCOMP(1)						      General Commands Manual						    X11PERFCOMP(1)

NAME

       x11perfcomp - X11 server performance comparison program

SYNTAX

       x11perfcomp [ -r | -ro ] [ -l label_file ] files

DESCRIPTION

       The  x11perfcomp program merges the output of several x11perf(1) runs into a nice tabular format.  It takes the results in each file, fills
       in any missing test results if necessary, and for each test shows the objects/second rate of each server.  If invoked with the  -r  or  -ro
       options, it shows the relative performance of each server to the first server.

       Normally,  x11perfcomp  uses  the first file specified to determine which specific tests it should report on.  Some (non-DEC :) servers may
       fail to perform all tests.  In this case, x11perfcomp automatically substitutes in a rate of 0.0  objects/second.   Since  the  first  file
       determines  which  tests  to  report  on, this file must contain a superset of the tests reported in the other files, else x11perfcomp will
       fail.

       You can provide an explicit list of tests to report on by using the -l switch to specify a file of labels.  You can create a label file	by
       using the -label option in x11perf.

OPTIONS

       x11perfcomp accepts the options listed below:

       -r	       Specifies that the output should also include relative server performance.

       -ro	       Specifies that the output should include only relative server performance.

       -l label_file   Specifies a label file to use.

X DEFAULTS

       There are no X defaults used by this program.

SEE ALSO

       X(7), x11perf(1)

AUTHORS

       Mark Moraes wrote the original scripts to compare servers.
       Joel McCormack just munged them together a bit.

X Version 11							   x11perf 1.5.4						    X11PERFCOMP(1)
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