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Date:      Fri, 18 Nov 2016 11:58:01 +0100
From:      Polytropon <freebsd@edvax.de>
To:        Matt Smith <matt.xtaz@gmail.com>
Cc:        "Christoph P.U. Kukulies" <kuku@kukulies.org>, "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org>
Subject:   Re: how long does a make buildworld normally take?
Message-ID:  <20161118115801.4ef94f0d.freebsd@edvax.de>
In-Reply-To: <20161118101752.GA39102@gmail.com>
References:  <b3bc55ef-5389-0f46-752a-290a45ee97fc@kukulies.org> <20161118101752.GA39102@gmail.com>

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On Fri, 18 Nov 2016 10:17:52 +0000, Matt Smith wrote:
> On Nov 18 10:38, Christoph P.U. Kukulies wrote:
> >how long does a make buildworld normally take?
> >Has make buildworld time constant over the years?
> >
> >
> >In 1995 "make world" on a Pentium Pro about 18 hours
> >On my 4GB, CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ 
> >(1995.64-MHz 686-class CPU)
> >make buildworld took about 18 hours. Well that CPU isn't the latest 
> >either (10 Years or so)
> >
> 
> 18 hours?! On my current home-server which is an Intel Atom D525 1.8ghz 
> it only takes 5 hours. And these are not known for being fast at all.

Allow me to quote from a message I wrote in 2008, in order to
illustrate technical progress by collectingg several build times
for different world and kernel configurations.

FreeBSD 5 on Pentium 4 with 2 GHz and 1 GB RAM:

b.world+b.kern:	17494.415u 2562.134s 5:46:42.25 96.4% (with CFLAGS)
		17474.169u 2481.368s 5:46:30.40 95.9% (without CLFAGS)
		 5608.712u 1595.130s 2:13:18.67 90.0%
		 6382.185u 1788.433s 2:26:36.06 92.8%
buildworld:	 5086.993u 1431.086s 1:58:16.33 91.8%
		11457.047u 2151.158s 3:54:15.31 96.8%
buildkernel	 2326.380u  234.457s   43:42.15 97.6%
		 1102.491u  278.194s   25:18.58 90.9%
		 1182.203u  294.622s   26:12.71 93.9%
		 1518.402u  310.741s   34:16.96 88.9%
		 3289.368u  529.669s 1:05:25.90 97.2%
installkernel:	    5.718u    6.898s    0:30.97 40.6%
		    6.655u    7.389s    0:32.08 43.7%
		    6.994u    7.734s    0:33.19 44.3%

(...software advance happens here...)

FreeBSD 7 on Pentium 4 with 2 GHz and 1 GB RAM:

b.world+b.kern:	16574.070u 2516.128s 6:06:03.90 86.9% (with debug)
		18232.967u 2427.404s 7:19:49.24 78.2% (with debug)
		18992.839u 2569.146s 9:12:00.28 65.1%
buildworld:	11457.047u 2151.158s 3:54:15.31 96.8%
buildkernel:	 3289.368u  529.669s 1:05:25.90 97.2%
		 3503.732u  524.399s 1:11:05.53 94.4%
		 4032.019u  572.636s 1:58:29.08 64.7% (with debug)
installkernel:	   17.396u   12.587s    0:46.89 63.9%
		   18.890u   12.131s    1:11.85 43.1%

As you can see, 5 hours was a possible value on a single-core
single-threat slow-as-ass CPU. But then the system became more
advanced, and 7 - 9 hours compile time became possible. :-)



> In 
> 1996 ish I was doing it on something like a pentium 75 and I think it 
> still took about 5 hours. So you're right there! 18 hours seems way too 
> long though.

On my first FreeBSD machine, compiling world and kernel needed
approx. 24 hours. The kernel itself could be rebuilt in more or
less 6 hours. Today we have loadable modules. :-)



> These days it compiles things like clang which take a very long time.

But it also introduces optimization which the "old compilers" did
not provide, so by investing more build time, you get a better
runtime experience (programs run faster). Especially on limited
hardware, this is worth considering (like in ye olde days setting
several "strange" CFLAGS to make mplayer perform better).



-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...



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