Re: diskd Q1/Q2 parameters backwards

From: Henrik Nordstrom <hno@dont-contact.us>
Date: Mon, 7 Jan 2002 22:18:30 +0100

Hmm.. are you sure? From what I can tell Q1 = 64, Q2 = 72. Looking at HEAD
and 2.4.

The comments in squid.conf and the FAQ has been backwards some time, but
this should have been corrected long ago..

To re-summary the limits:

Really bad things happens if you reach the upper SHM limit.

To avoid this, there MUST be a reasonable margin where you start block
new I/O requests.

To avoid too much blocking, there SHOULD to be a limit where you starts to
reject new I/O requests.

Q1 controls the rejection limit (magic1)

Q2 controls the blocking limit (magic2).

The C code is written such that Q1(64) < Q2(72) < SHM limit(96), and is
also how it is documented in squid.conf.default as far as I can tell.

If you find any errors in the above in either my spongy brain, this
message, documentation or implementation, please correct, whereever the
error is.

Regards
Henrik

On Monday 07 January 2002 18.20, Duane Wessels wrote:
> The Q1 and Q2 parameters are backwards in the current releases.
>
> The C code is written such that Q1 > Q2 (i.e. Q1=72, Q2=64).
>
> However, the squid.conf comments, the defaults, and perhaps other
> places say that it should be Q1=64, Q2=72. Really bad things happen
> when you use these values and the load reaches those queue limits.
>
> Any preferences on what should be changed to make this right? I
> guess my preference is to leave the implementation alone and change
> squid.conf and the hard-coded defaults.
Received on Mon Jan 07 2002 - 14:20:06 MST

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