Re: [HACKERS] Compile timing - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [HACKERS] Compile timing
Date
Msg-id 199909231442.KAA14756@candle.pha.pa.us
Whole thread Raw
In response to Re: [HACKERS] Compile timing  (Thomas Lockhart <lockhart@alumni.caltech.edu>)
List pgsql-hackers
> > Not sure why -j2 is not faster than normal -j...
> 
> I was just looking at this a little while ago at work. It is not
> faster because gmake does not propagate the "-j2" flag to submakes, on
> the (correct) theory that you might get a geometrically growing system
> load, rather than just keeping two makes running through all the
> subdirectories.
> 
> This is the behavior of "-j", unless you specify it without a numeric
> parameter, in which case it *does* allow parallel submakes.
> 
> The first time I tried "-j", I did it without reading the man pages
> and without specifying a numeric parameter. It did a magnificent job
> of bringing down my system trying to build ACE/TAO, a *large* Corba
> package. Chewed up all of real memory, then all of swap; not sure if I
> ran out of process slots or memory first but it wasn't pretty. It was
> *very* fast though :)
> 

Yes, make -j without a number does so many makes here the compile fails
too, and the load average soars.

--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026
 


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