RE: [squid-users] Help Needed: Any suggestion on performance downgrade after enable Cache Digest?

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@creative.net.au]
>> Sent: Monday, April 21, 2008 11:48 PM
>> To: Zhou, Bo(Bram)
>> Cc: squid-users@squid-cache.org
>> Subject: Re: [squid-users] 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
>> >
>>
>> --
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Received on Tue Apr 22 2008 - 13:04:42 MDT