Re: [HACKERS] Compile timing

> Lamar Owen wrote:
>
> >
> > Bruce Momjian wrote:
> > >
> > > Someone mentioned that it took them quite a while to compile the
> > > PostgreSQL code. My wallclock time is 3:52 for a compile with -O1 using
> > > gcc 2.7.2.1. This is on a dual-PII 350MHz running BSD/OS 4.01.
>
> Hmmm,
>
> Is there something wrong with your system, Bruce? My 64MB
> 333MHz singe-PII (same gcc version under Linux 2.2.10) does a
> -O1 clean-compile in 3:28.
>
> Maybe the SMP overhead is eating up the missing cycles. You
> would like a parallelized make to outperform me again - no?

I knew someone would find this an interesting topic.

I should also mention I have 256MB of RAM, and Baracuda SCSI-Ultra
drives with tagged queuing enabled.

OK, I turned off my custom flags, and got for -O1:

real 3m8.080s
user 2m21.752s
sys 0m35.291s

I usually do:

CUSTOM_COPT=-g -Wall -O1 -Wmissing-prototypes -Wmissing-declarations

My bet is the symbol output takes some time to produce. I noticed the
link of the postgres binary was faster without -g.

With parallelization, using gmake -j2, I got:

real 3m8.980s
user 2m23.442s
sys 0m36.142s

Not sure why -j2 is not faster than normal -j, unless gmake knows to use
-j2 on a 2-cpu system by default. Looking at the xps output, I don't
see multiple compiles being performed by gmake.

Gmake -j fails because compiles happen before supporting files are
created.

--
Bruce Momjian | http://www.op.net/~candle
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