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X-WM-Posted-At: avacado.atomice.net; Fri, 26 Jul 02 22:27:58 +0100
Message-ID: <003f01c234eb$5036e910$0100a8c0@atomice.net>
From: "Chris January" <chris AT atomice DOT net>
To: <cygwin AT cygwin DOT com>
References: <31CB870AD5AA384BB5419025DD9F7A84104345 AT dailymail DOT cfs DOT ac DOT uk> <004201c234e5$7ec72250$0100a8c0 AT atomice DOT net> <20020726212251 DOT GB3404 AT redhat DOT com>
Subject: Re: a way to read the current cpu load from the shell or via a cmdline utility  in cygwin?
Date: Fri, 26 Jul 2002 22:27:58 +0100
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> >The values seem to be a factor of 10 out.
> >This is because Linux uses a value of 100 for HZ, whereas Cygwin has this
> >defined as 1000. The /proc implementation uses 100 and ignores the Cygwin
> >value.
>
> Is the cygwin value wrong?  Should we change it?
Which value you pick is completely arbitary. I chose 100 because that's the
same as Linux. I could just as easily re-write the /proc stuff to use HZ
from sys/param.h instead. The procps proc/sysinfo.c file has code to
automatically work out what value of HZ is being used by the kernel, so
existing binaries would still work without re-compilation.
The author of procps has this to say:
 * Some values in /proc are expressed in units of 1/HZ seconds, where HZ
 * is the kernel clock tick rate. One of these units is called a jiffy.
 * The HZ value used in the kernel may vary according to hacker desire.
 * According to Linus Torvalds, this is not true. He considers the values
 * in /proc as being in architecture-dependant units that have no relation
 * to the kernel clock tick rate. Examination of the kernel source code
 * reveals that opinion as wishful thinking.
So, no, I don't think it should be changed. Well written programs should be
able to cope with this. I will modify fhandler_process.cc and
fhandler_proc.cc to use HZ from sys/param.h.

Chris



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