Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 22 Nov 2001 16:32:37 -0700 (MST)
From:      Ronald G Minnich <rminnich@lanl.gov>
To:        Harti Brandt <brandt@fokus.gmd.de>
Cc:        Mike Meyer <mwm@mired.org>, <freebsd-hackers@FreeBSD.ORG>
Subject:   Re: sysctls for hardware monitoring?
Message-ID:  <Pine.LNX.4.33.0111221630400.24090-100000@snaresland.acl.lanl.gov>
In-Reply-To: <20011122103611.V451-100000@beagle.fokus.gmd.de>

next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, 22 Nov 2001, Harti Brandt wrote:

> What's bad about using files? Just to be different? Isn't it easier to
> select, poll, kqueue, what ever on files than on sysctls?

/proc files are horrible if you sample at reasonable rates, say 10-100 hz.
We found (on Linux, maybe fbsd is better) that sampling rpc.rstatd at 10
hz.  ate 10% of a 500 Mhz. PII. ouch. We also found that sampling
rpc.rstatd took > 10 MILLISECONDS on the same machine.

Moving to sysctl we found we could sample at 1Khz. with no significant
load on the machine.

See the Supermon paper at ALS2001 for more info.

ron


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.LNX.4.33.0111221630400.24090-100000>