Which OS? If Linux, did you start looking at the CPU use using oprofile?
Adrian On Mon, Apr 21, 2008, Zhou, Bo(Bram) wrote: > Hi, > > Recently I did some interesting performance testing on the Squid configured > with Cache Digest Enabled. The testing result shows that the Squid use more > than 20% CPU time than the Squid running without Cache Digest. Following are > my detailed testing environment and configuration and result. Anyone can > give me some light on the possible reason will be greatly appreciated. > Please also point out the possible configuration errors if any. Thanks a > lot. > > 1. Hardware configuration : HP DL380 > (1) Squid Server > CPU: 2 Xeon 2.8GHz CPUs, each Xeon CPU has 2 Cores > Memory size: 6G, Disk: 36G, NIC: 1000M > (2) Client and Web Server : Dell Vostro200 running with Web Polygraph 3.1.5 > > 2. Squid Configuration > (1) 2 Squid instances are running on the same HP server, each using same IP > address but different PORT, pure in memory cache > Squid1 configuration: > http_port 8081 > cache_mem 1024 MB > cache_dir null /tmp > cache_peer 192.168.10.2 sibling 8082 0 proxy-only > digest_generation on > digest_bits_per_entry 5 > digest_rebuild_period 1 hour > digest_swapout_chunk_size 4096 bytes > digest_rebuild_chunk_percentage 10 > > Squid2 configuration: > http_port 8082 > cache_mem 1024 MB > cache_dir null /tmp > cache_peer 192.168.10.2 sibling 8081 0 proxy-only > digest_generation on > digest_bits_per_entry 5 > digest_rebuild_period 1 hour > digest_swapout_chunk_size 4096 bytes > digest_rebuild_chunk_percentage 10 > > 3. 2 Polygraph Clients are used to send HTTP requests to Squid instances. > Different client send request to different Squid instance. Each client > configures 1000 users with 1.2 request/s, so totally each client send 1200 > requests/s. > > 4. Test result (Note: since 4 CPU used on the server, the total CPU > utilization is 400%) > (1) Running 2 Squid instances with Cache Digest Enabled, each handles 1200 > request/second: > Each instance used ~95% CPU even during the time Squid didn't rebuild the > digest > > (2) Running 2 Squid instances with Cache Digest Enabled, one handles 1200 > request/second, one is idle(no traffic to it) > The one with traffic has CPU utilization ~65%, the other one is idle > > (3) Running 2 Squid instances with Cache Digest Disabled, each handles 1200 > request/second: > Each instance used ~75% CPU > > > Best Regards, > Bo Zhou > -- - Xenion - http://www.xenion.com.au/ - VPS Hosting - Commercial Squid Support - - $25/pm entry-level VPSes w/ capped bandwidth charges available in WA -
