Re: Help!!

> On Mon, 3 Jul 2000, jubaco30 wrote:
> > I need to know urgently(An Administrative Decision) if squid takes
> > advantage of SMP (Redhat 6.2 with 2 processors). The main questions is
> > if the granularity of locks in I/O lead to similar performance(with
> > smp, without smp)?.
>
> It is my understanding that Squid is implemented as a single process with
> its own internal state machine/executive to manage its activity.

Under Linux it multi-threads if you enable ASYNCIO, which means it scales
much better over multiple separate disks (without RAID).

> Under BSD/OS 4.x, Squid's apparent performce improved dramatically on
> multi-processor systems. The observed performance improvement on the dual-
> and quad-processor systems that we have is more a function of how well the
> OS manages its resources and activities in an SMP environment.

Under BSD/OS you're likely to not be using ASYNCIO, so you have limited
gain from SMP for Squid, but there is still some gain there.

> While we do have a few Linux systems, we tend to use BSD/OS where the
> leather meets the road. This is probably more a function of two decades of
> experience with the Berkeley Software Distribution from CSRG and BSDi.

Well we use it too (as a result of policy, not of choice) but the number
of bugs and lack of development tools is just damn annoying to people
who are used to something as robust and well supported for development as
Linux. Fortunately Squid doesn't hit many of the bugs (but OTOH it doesn't
do ASYNCIO under BSD/OS which is a bit of a performance pain, but can be
countered by just buying faster boxes than you would need to with Linux).

David.

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David Luyer
Senior Network Engineer
Pacific Internet (Aust) Pty Ltd
Phone:  +61 3 9674 7525
Fax:    +61 3 9699 8693
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