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Re: Questions re Zmail
On Mon, 19 May 1997, Christoph Lameter wrote:
> On Mon, 19 May 1997, Andy Poling wrote:
> >On Mon, 19 May 1997, Christoph Lameter wrote:
> >> 1. What is this "Timeserver" and why does it garble the ps line?
> >> 11831 ? S 0:00 /usr/lib/zmailer/router -dkn 4
> >> 11836 ? S 0:04 /usr/lib/zmailer/scheduler -l /var/log/mail/scheduler.perflog -S -H
> >> 11837 ? S 0:00 TimeServer ailer/scheduler -l /var/log/mail/scheduler.perflog -S -H
> >> 11838 ? S 0:00 /usr/lib/zmailer/router -dkn 4
> >> 11839 ? S 0:00 /usr/lib/zmailer/router -dkn 4
> >It is responsible for serving the current date/time. I guess the idea is
> >that, at maximum, one gettimeofday() per second will occur due to the
> >scheduler. On a busy mail system it could be a significant win.
> Why would a daemon be more efficient than the kernel code?
> Also I am running xntp on that host. The kernel time is really accurate.
> The "TimeServer" is useless AFAIK.
You don't get it. The TimeServer reduces the number of syscalls.
Rather doing a gettimeofday() for every message, it only does it once a
second. The time is written into shared memory. You will see that it is
used all over the place in the scheduler code.
xntpd is actually quite useless. The scheduler does not need accurate
time of day, but just the time between events.