Adrian, I'm using RHE4 with kernel 2.6.9. I used top to collect CPU utilization and didn't use oprofile but just installed. I will use it to do profiling in the later testing session. Thanks for your reminder. Best Regards, Bo Zhou >> -----Original Message----- >> From: Adrian Chadd [mailto:adrian@xxxxxxxxxxxxxxx] >> Sent: Monday, April 21, 2008 11:48 PM >> To: Zhou, Bo(Bram) >> Cc: squid-users@xxxxxxxxxxxxxxx >> Subject: Re: Help Needed: Any suggestion on performance >> downgrade after enable Cache Digest? >> >> >> 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 -
