r583 - in trunk/varnish-cache: bin/varnishd include

[Poul-Henning Kamp]

In message <20060801093953.4C6CF1EC3EB at projects.linpro.no>, phk at projects.linpro
.no writes:

>SHMlog the start and difference between start and stop with ReqServTime
>tag.

I just ran a very quick live-test to see the distrbution of our
service time.

For both hits and misses we have a "hockey-stick" figure with
a small percentage of the transactions accounting for a large
part of the average.

The tables below show the numbers for the the entire dataset and
for the 99, 95, 90 and 75% fastest of the dataset.

Notice how rapidly the Max value falls off.

Since some of the hits may actually have been waiting on a busy
object while another session filled it from the backend, I think
it is fair to say that a "un-encumbered" hit takes less than
100 usec and typically less than 50usec to process.

Poul-Henning

===> hit
        N           Min           Max        Median           Avg        Stddev
100% 5196    24.865e-06   0.002863344     44.98e-06 54.471059e-06 46.992297e-06
 99% 5144    24.865e-06   0.000150585     44.98e-06 52.087417e-06 16.672175e-06
 95% 4936    24.865e-06    86.886e-06    44.701e-06 49.620993e-06 11.263975e-06
 90% 4676    24.865e-06    77.387e-06    44.421e-06 47.891206e-06 8.7613014e-06
 75% 3897    24.865e-06    51.406e-06    43.862e-06 44.476003e-06 2.5034017e-06

===> fetch
       N           Min           Max        Median           Avg        Stddev
100% 701   0.002255418     13.741159   0.010918089    0.21945862    0.87530516
 99% 693   0.002255418     2.5146695   0.010593451    0.14724379     0.3537625
 95% 665   0.002255418     1.0104925   0.009807282   0.086928877    0.18072753
 90% 630   0.002255418    0.50737959   0.009042904   0.052588283    0.10405137
 75% 525   0.002255418   0.089049749   0.006494698   0.013066963   0.015961684

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.