Re: 2nd-biggest Squid performance problem?

From: Jon Kay <jkay@dont-contact.us>
Date: Thu, 27 Sep 2001 15:14:35 +0000

Andres, this is some mighty fine work. I did something similar with
Tahoe TCP/IP, so I can appreciate the work involved here. Only, I
had to use a logic analyzer to get good timings, at vast pain - you
young'uns, you probably didn't even have to walk to school every day
through six feet of snow. Except maybe Henrik :-).

Now, I am trying to understand which probe name corresponds to what
part of Squid. Is there a probe that roughly corresponds with read()
calls, the rough correspondent of commHandleWrite?.

Good business looking at prep_pfds. Is that what it looks like, the
loops in which the select() fdsets are set up? Is handle_ready_fd the
corresponding figuring out which fds are ready?

What is UNACCOUNTED? Any idea where the extra 30% comes from (I know,
it's hard to nail that down, I only got it to within 12% after a year
of work, I'm mostly just randomly curious)?

Pity we can't get at what part of the select call is overhead and what
part is idle time.

I'm surprised that read_handler is so small, my uneducated guess would
have pegged it at 50% higher.

                                                Jon
Received on Thu Sep 27 2001 - 21:16:42 MDT

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