RE: Gack, this shouldn't happen under a stable OS I think

Michael Beach (mbeach@awa.com.au)
Mon, 23 Sep 1996 17:05:46 +-1000

Depends on the order in which the shell and the children it forks are scheduled. If the grep gets scheduled before the ps you will see it, if not, you won't.

Regards
M.Beach

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From: Jon Lewis[SMTP:jlewis@inorganic5.fdt.net]
Sent: Monday, 23 September 1996 10:46
To: Chris Fearnley
Cc: Linus.Torvalds@helsinki.fi; alan@lxorguk.ukuu.org.uk; linux-kernel@vger.rutgers.edu
Subject: Re: Gack, this shouldn't happen under a stable OS I think

On Sun, 22 Sep 1996, Chris Fearnley wrote:

> Alan had me on the look out for dropping bytes regarding my recent
> "TCP bug" report. I'm not sure I found that, but this inconsistency
> seems "bad" to me. The worse part is the behaviour is
> non-deterministic! Note: the system was mostly idle at the time.
>
> root@syntropy # ps aux|grep 27231
> root 27231 0.0 2.1 828 324 p7 S 23:28 0:00 /usr/sbin/radiusd
> root@syntropy # ps aux|grep 27231
> root 27231 0.0 2.1 828 324 p7 S 23:28 0:00 /usr/sbin/radiusd
> root@syntropy # ps aux|grep 27231
> root 27231 0.0 2.1 828 324 p7 S 23:28 0:00 /usr/sbin/radiusd
> root 27239 0.0 2.5 916 376 p7 S 23:28 0:00 grep 27231
>
> Why doesn't the grep process show up each time???

I've seen this sort of thing plenty of times. A better question might be
why does the grep show up at all, or why isn't it consistant? Isn't the
ps finished by the time grep runs?

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