On Wed, 15 Sep 2010 20:53:04 +0100, Martin Sperl <Martin.Sperl@xxxxxxxxxx> wrote: > Hi Amos! > > Thanks for your feedback. > >> Squid is still largely IO event driven. If the network IO is less than >> say 3-4 req/sec Squid can have a queue of things waiting to happen which >> get delayed a long time (hundreds of ms) waiting to be kicked off. >> Your overview seems to show that behaviour clearly. >> >> There have been some small improvements and fixes to several of the >> lagging things but I think its still there in even the latest Squid. > > Here the Hit/s statistics on this specific server for the time: > +------+-------+-------+ > | h | allHPS| cssART| > +------+-------+-------+ > | 0 | 48.34 | 0.016 | > | 1 | 49.80 | 0.015 | > | 2 | 49.01 | 0.015 | > | 3 | 47.08 | 0.018 | > | 4 | 17.34 | 0.024 | > | 5 | 4.00 | 0.042 | > | 6 | 0.52 | 0.054 | > | 7 | 9.02 | 0.034 | > | 8 | 7.18 | 0.038 | > | 9 | 8.25 | 0.035 | > | 10 | 9.45 | 0.034 | > | 11 | 14.71 | 0.030 | > | 12 | 23.94 | 0.023 | > | 13 | 31.04 | 0.021 | > | 14 | 35.02 | 0.020 | > | 15 | 38.87 | 0.019 | > | 16 | 40.92 | 0.019 | > | 17 | 43.39 | 0.017 | > | 18 | 45.62 | 0.016 | > | 19 | 47.58 | 0.017 | > | 20 | 51.91 | 0.014 | > | 21 | 53.65 | 0.014 | > | 22 | 40.87 | 0.016 | > | 23 | 47.40 | 0.016 | > +------+-------+-------+ > > So to summarize it: we need to keep the number of hits above 30 hits/s for > squid, so that we get an acceptable Response time. > > I believe it will need some convincing of management to get this > assumption tested in production ;) > > One other Question: is squid 3.1 "better" in this respect than 3.0? Than 3.0? I believe so. Though have no data on it. The upper req/sec cap where the most effort has gone is 15%-20% higher, I have not done any serious testing like this with the lower limits before. If you are able to it would be very enlightening and helpful for many I think. Amos
