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From Aaron Bannert <aa...@clove.org>
Subject Re: Strange Behavior of Apache 2.0.43 on SPARC MP system
Date Tue, 11 Feb 2003 18:08:29 GMT
A couple questions and a couple observations:

1) How many network cards are in the server? (How many unique
    interrupt handlers for the network?)

2) How much context switching was going on, and how impacted
    were the mutexes (see mpstat)?

3) Was the workload uniformly distributed across the CPUs?

I've seen large MP systems completely fail to distribute the
workload, and suffer because of it. My current theory for why
this occurs is that the interrupt load is overwhelming the CPU
where that interrupt is being serviced. This combined with the
relatively small amount of userspace work that must be done to
push a small static file out is wreaking havoc on the scheduler
(and it's probably more dramatic if your system enabled sendfile
support).

-aaron


On Tuesday, February 11, 2003, at 09:34  AM, Min Xu wrote:

> Thanks to Owen Garrett, who reminded me that I should have
> mentioned a little more details about the client configuration.
>
> My modified SURGE client fetch web pages on an "object" basis,
> each object contains multiple pages. For each object the client
> uses HTTP/1.1 keepalive, but not pipeline. After an object
> being fetched completely, the client close the connection
> to the server and reopen a new one for next object.
>
> The delay time I added was between each web pages, so the
> client goes to sleep for a little while with the connection
> being still open.
>
> FYI, I have attached the client code. Anyone have a wild guess
> on what's going on? ;-) Thanks a lot!


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