Thanks for the replying Amos, I am going to test with CPU affinity with multi-core, * i will run multiple squid instances in multi-core , that is each instance run in specific core, for example squid1 in CPU #0 and squid2 in CPU #1 * with iptables using --probability to load balance the squid * for caching , instances have separate cache_dir with cache_peer balancing before trying this i wish to know , it will give better performance ? Thanks -Viswa On Wed, Aug 24, 2011 at 6:05 PM, Amos Jeffries <squid3@xxxxxxxxxxxxx> wrote: > On 24/08/11 21:46, viswanathan sekar wrote: >> >> Hi All, >> >> I had an argument with my friends telling them that mulitple squid >> instances in multi-core processors will give better performance with >> iptables load balancing. >> Some of my friends disagreed with me telling single squid instance >> will give same performance. >> >> I am really confused, >> >> which will give better performacne from the above two? >> >> Is squid IO bound or CPU bound ? > > Both. > > - instances using cache_dir tend to be disk I/O bound > - instances using only memory caching tend to be network I/O bound > - instances doing much ACL filtering tend to be CPU bound > > With >2 cores you can mix these types to get better overall performance in > one area or another. > > > As for iptables; > > So far I have had two people indicating a nice req/sec increase using: a > single instance, single core utilized, identical config, only changing 2 vs > 1 http_port receiving traffic. We don't know why precisely, I do know that > two ports means Squid does two accept() per cycle of FD checking. > (I forget what the actual increase % mentioned was, no strict measurements > were taken though). > > NOTE: iptables is just a way of presenting client with one port and using > this effect for two ports in the background. Same effect was seen with other > non-iptables methods of spreading the load over two ports (round-robin DNS > in the one case of that. I expect PAC selection of an instance port would > work too). > > Nice project in there if someone wants to research its reliability and > measure the actual gain/loss metrics. > > > NP: Squid makes _extreme_ demands of the disks. If there is anything getting > in between or trying to utilize them for other purposes (including RAID) the > disk I/O performance is degraded. Sometimes a lot. > > > Amos > -- > Please be using > Current Stable Squid 2.7.STABLE9 or 3.1.14 > Beta testers wanted for 3.2.0.10 >
