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Re: race condition with reap_children when $(shell) used


From: Grant Taylor
Subject: Re: race condition with reap_children when $(shell) used
Date: Sun, 11 May 2003 15:33:33 -0400

> It is impossible to use the load average on its own to get good
> control over job spawning, you always wind up with a spike that
> brings a system to its knees. It was a bad idea from day one.

Of course, it's intended more as a "nice" feature for other users so
that when a system is busy make doesn't always run the -j number of
jobs.

>> IMHO it's entirely reasonable to specify something like -j8 -l4;

> When you're using tokens the load average specifier is completely
> superfluous. You're guaranteed that at most 8 jobs will be
> active. If you have 8 jobs running and the load average is less than
> 4, you won't get more jobs spawned to bring the load average up to
> 4. It's completely useless - harmful when used by itself, and
> pointless when tokens are in use.

No, it's entirely useful.  The intent of -l is only to limit the
impact of a make on other users.  It does in fact work well when used
this way; if two people run make -j8 -l4, their makes will tend to
back off so that the system won't crawl.

Anyway, regardless of what one is supposed to *use* these features
for, they've got bugs, and that's my main concern.

--
Grant Taylor - address@hidden - http://www.picante.com/~gtaylor/
  Linux Printing Website and HOWTO:  http://www.linuxprinting.org/




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