On Fri, 8 Mar 2002, Joe Cooper wrote:

> You're probably right about this.  In many cases the benefits of threads 
> outweigh the performance troubles--and Oops does a fine job keeping up 
> with Squid up to a point and uses less resources to do it, generally. 
> And achieving the absolute pinnacle of performance doesn't usually need 
> to be the most important factor when designing any software.  But then, 
> threads also introduce a lot of their own problems that make debugging 
> and maintaining the code more difficult.  The fact that many Unix and 
> Linux developers don't /like/ threads and so don't spend much effort 

It's pity. Multithreading is only real way to use several processors on the
host.

> I did some benchmarking of Oops 2.2.18 and some 2.2.x version after 
> 2.2.18 (it was one of the experimental tarballs).  I found it to perform 
> extremely well at low request rates and client loads, but found 
> performance topped out at 70 reqs/sec from hardware that could sustain 
> about 110 from Squid.  Because CPU wasn't a bottleneck, and I had plenty 
> of memory, I had to assume the biggest problem was disk I/O contention 
> with the BerkelyDB.  So GigaBASE addresses this problem, somewhat?

If CPU is not a bottleneck then most probably disk I/O with storages (and
next with DB) is the problem. Since 1.5.18 there were significant
improvements in storage I/O area. In test environment (under polygraph)
due to aligned read/write to raw partition, speed of document swapout
increased near 5 times.

There was also some changes in swapout/dropout algorythms which allow keep
memory usage under more constant control.

Again, to avois OS-specific performance problem you should try it under
solaris.

> 
> I'm not convinced that a DB style backend can provide a satisfactory 
> performance level with multiple disks...but perhaps I'm wrong.  It is 

I never seen that gigabase become bottleneck, storage io become first.

> I'm quite impressed with Oops.  (That's why I'm on the list and have 
> done quite a bit of testing with it! ;-)  I do like the overall design 
> (with the caveat that I don't really know that threaded programming is 

Thanks for your words :)

> the Right Way).  It's quite likely that as it develops into something as 
> solid as Squid, and has the primary features that my clients need I will 

Which features?

> begin to support it alongside Squid.
> 
> And for what it's worth, I think the idea of starting from scratch 
> rather than patching Squid was probably a good one.  Even the Squid 
> developers seem to be leaning towards a near total rewrite for version 3 
> of Squid.  ;-)

I can understend them :). I also started to rewrite oops half year ago, when
I clear see what was wrong from the start.

Igor Khasilev                     |
PACO Links, igor at paco dot net  |


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