[Varnish] #1021: varnishtop -1 takes a long time to run
Varnish
varnish-bugs at varnish-cache.org
Mon Nov 5 11:26:45 CET 2012
#1021: varnishtop -1 takes a long time to run
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Reporter: yves | Owner: martin
Type: defect | Status: new
Priority: normal | Milestone:
Component: build | Version: 3.0.1
Severity: normal | Resolution:
Keywords: varnishlog |
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Comment (by daghf):
I did some testing for this, and it's not an api issue.
I was able to reproduce this by first running siege in benchmark mode for
a few minutes to build up a sizeable -d backlog of approx 2.5M vsl
records, of which around 15% of the records were unique. I'm guessing
these numbers are not entirely atypical for a live varnish server.
Simple profiling using valgrind uncovered that around 99% is spent in
accumulate(). Looking at the code the frequency table is built by keeping
a vtailq of known unique records - this list is then scanned for every
subsequent log record to see if it has already been encountered. When
number of -d records is in the millions, this gets costly.
--
Ticket URL: <https://www.varnish-cache.org/trac/ticket/1021#comment:4>
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