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From: davidsen@steinmetz.UUCP (Davidsen)
Newsgroups: net.lang.c
Subject: Re: Datalight faster than 4.2, why?
Message-ID: <761@steinmetz.UUCP>
Date: Thu, 22-May-86 16:16:59 EDT
Article-I.D.: steinmet.761
Posted: Thu May 22 16:16:59 1986
Date-Received: Sat, 24-May-86 17:38:48 EDT
References: <989@dataioDataio.UUCP>
Reply-To: davidsen@kbsvax.UUCP (Davidsen)
Organization: GE CRD, Schenectady, NY
Lines: 65

In article <989@dataioDataio.UUCP> bjorn@dataio.UUCP writes:
>I'm sitting here, moving our latest software product down to the IBM PC,
>waiting for it to compile, and I notice this (odd) fact: the compiler
>on the PC is better than the one on the VAX!  It's faster, it produces
>better code, and it catches errors that the UNIX C does not.  So I'm
>curious:
>	The state-of-the-art in compilers has progressed on PCs,
>	so why hasn't anyone come up with a better compiler for
>	UNIX, or have I just not heard of it?
>
>For your information I'm running UNIX 4.2bsd with the standard C 
>compiler on a VAX 11/750, and Datalight C 2.04 on an IBM PC/AT under
>MSDOS 3.0.  The PC takes 5 minutes 26 seconds to compile 7605 lines of 
>code in 29 files (plus 735 lines of header in 13 files), whereas the unloaded
>VAX (load average 1.13) takes 8 minutes 30 seconds.  All the outside 
>influences were indentical: debugging, optimization, etc.
>
>					Bjorn N Freeman-Benson
>					FutureNet, a Data I/O company

I have a UNIX benchmark suite which I run everywhere I can to give me an
idea of the relative speed of various boxes. The reason that stuff
compiles faster on the AT is that the 750 isn't that much faster than an
AT, and the VAX is probably loaded. The following info is from benchmarks
I took in the last year, AT running SCO Xenix/286, VAX 750 running SysV
(*not* 4.2).

Test			AT	750
integer Kops/sec	358.2	364.1
float Kops/sec		 23.8	 39.5
Branch and compare K/sec
  int			183.8	246.7
  float			 11.2	138.5

trig functs op/sec	1159	1020

avg access 2MB file/ms	23.2	 8.2

pipes Kbytes/sec	304.8	276.8
systemcalls K/sec	  4.0	  3.4

----------------------------------------------------------------
What this shows is that (a) an AT souped up to 9MHz or so and given a
better disk is that it is a really nice 1-2 user system (given realistic
memory), and (b) that even a stock AT is faster than whatever fraction of
a VAX you can actually get in most places.

As for compiler checking, I completely agree with you. The Microsoft C
compiler catches things that slip past lint, and the v4.0 (I doing beta
test) is even better! The nice thing about PCC is that's is portable, and
anyone who's ever moved UNIX code to other compilers (PCDOS, Xenix, VAX-C)
may find that the code either won't compile or runs much faster but
doesn't work.

Hope this explains why the AT looks so good, it is.
-- 
	-bill davidsen

  ihnp4!seismo!rochester!steinmetz!--\
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                    unirot ------------->---> crdos1!davidsen
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         sixhub ---------------------/        (davidsen@ge-crd.ARPA)

"Stupidity, like virtue, is its own reward"