From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joern Rennecke To: Joe Buck Cc: Andreas Schwab , Richard Henderson , Brad Lucier , Michael Matz , gcc@gcc.gnu.org Subject: Re: if-conversion a performance bottleneck Date: Wed, 10 May 2000 14:17:00 -0000 Message-id: <200005102115.WAA30491@phal.cygnus.co.uk> References: <200005101628.JAA25911@possibly.synopsys.com> X-SW-Source: 2000-05/msg00445.html > No, -l does not work and never did. The reason is that the load value > increases very slowly as processes are launched; as a result, if you > say make -j -l, a very large number of processes get launched initially, > and it may take 10 seconds or so for the load to climb to the level > specified in -l -- but then the load climbs to 20x that figure or more. > At this point, no more processes get launched until at least a minute > after all of the first batch dies, and then another process storm is > launched. This is becuase the number checked by -l is based on an average > load over a full minute, not an instantaneous figure. > > Solution: get make 3.79 and use -j. The GNU make folks should > deprecate -l and eventually remove it. I wouldn't go so far. It seems clear that -l is not useful to make make react to the load it creates itself, but you might use it instead or in addition to nice to control how much a batch job taxes a system that is used for interactive stuff as well.