RE: [squid-users] Help understanding calamaris/squid output

> -----Original Message-----
> From: Scott Presnell [mailto:srp@tworoads.net]
> Sent: Monday, April 18, 2005 8:40 AM
> To: squid-users
> Subject: [squid-users] Help understanding calamaris/squid output
>
>
> HI Folks,
> I'm running Squid Cache: Version 2.5.STABLE7 under NetBSD 2.0
> and I'm using calamaris to try and track performance. Calamaris seems
> to be telling me that my TCP_REFRESH_HIT speed performance is poor;
actually
> lower than my MISS performance. I have some questions:
>
> 1) Why would this be true? Overhead of the IMS test + the actual request?
> local disk performace issues? What can I do to further interrogate and
increase
> the performance of this kind of request/response?

It's not... TCP_REFRESH_HITs are taking 0.2 seconds to complete. Your
fastest MISS (TCP_CLIENT_REFRESH_MISS) is taking twice as long. If you are
looking at the kB/sec speed, then you must realize that small transfers (as
a TCP_REFRESH_HIT will be) suffer from TCPs slow start. Nothing you can do
about that.

>
> 2) Given the definition of TCP_REFRESH_HIT:
>
> The requested object was cached but STALE. The IMS query for the object
resulted in "304 not modified".
>
> ... then what is the difference between TCP_REFRESH_HIT/200 and
TCP_REFRESH_HIT/304?

TCP_REFRESH_HIT/200 = Object was cached, and not marked as stale.

TCP_REFRESH_HIT/304 = Object was cached, marked as stale, but the request to
the origin server returned "304 Not Modified".

>
> Thanks for any help.
>
> - Scott
>
> # Incoming TCP-requests by status
> status request % sec/req Byte %
kB/sec
> ------------------------------ --------- ------ ------- -------- ------
-------
> HIT 11599 54.81 0.12 11108299 6.26
7.95
> TCP_REFRESH_HIT 6572 31.06 0.20 6582553 3.71
4.94
> TCP_MEM_HIT 2929 13.84 0.01 2529904 1.43
79.90
> TCP_IMS_HIT 1136 5.37 0.01 262521 0.15
18.61
> TCP_HIT 942 4.45 0.02 1706470 0.96
92.35
> TCP_NEGATIVE_HIT 20 0.09 0.01 26851 0.02
141.74
> MISS 7279 34.40 1.53 156276K 90.15
14.00
> TCP_MISS 6579 31.09 1.64 149822K 86.43
13.89
> TCP_CLIENT_REFRESH_MISS 462 2.18 0.40 5698990 3.21
29.81
> TCP_REFRESH_MISS 238 1.12 0.80 909725 0.51
4.64
> ERROR 2283 10.79 0.72 6372629 3.59
3.78
> TCP_MISS 1718 8.12 0.96 5551109 3.13
3.30
> TCP_DENIED 564 2.67 0.00 819910 0.46
652.03
> TCP_REFRESH_MISS 1 0.00 0.05 1610 0.00
32.09
> ------------------------------ --------- ------ ------- -------- ------
-------
> Sum 21161 100.00 0.67 173347K 100.00
12.23
>

Chris
Received on Wed Apr 20 2005 - 12:26:46 MDT