Subject: Re: Compiler timings on varous MVII NetBSDs etc.
To: NetBSD Bob <nbsdbob@weedcon1.cropsci.ncsu.edu>
From: Kevin P. Neal <kpneal@pobox.com>
List: port-vax
Date: 01/23/2001 12:44:22
On Tue, Jan 23, 2001 at 11:50:04AM -0500, NetBSD Bob wrote:
> I am afraid I will have to side with Isildur on this one.
> 
> But, there is more too it that just feeping creaturitis.
> 
> Consider the bare kernel, as one issue.
> 
> On my 4.3BSD MVII VAX, the kernel takes 45 MINUTES to compile using
> pcc IN ONLY 7 MB of ram, and has a footprint of 273K.
> 
> On my NetBSD-1.5 MVII VAX, with 13mb of ram, using the SAME config
> for the kernel (basically stripped down to the minimal BSD bits),
> the kernel takes 25 HOURS to compile, and has a footprint of 580K.

Using the same compiler version?
 
> Consider functionality, e.g., ethernet throughput.
> 
> The code has improved in many areas, for example in the tcpip stacks
> the code has improved speed by almost 100% relative to 4.3BSD in
> throughput, on NetBSD-1.4.3.  But, 1.5 has dropped back to only a 50%
> improvement.
> 

And this isn't caused by swapping or some other factor outside of the
network stack?

> Consider compiler efficiency.
> 
> A simple program such as gkermit takes 2:50 to compile in Ultrix 4.2,
> 3:01 to compile in 4.3BSD, and 7:40 to compile in NetBSD-1.5.  What is
> wrong with that picture?  The compiler is slowing down, tremendously.
> Interestingly, binary bloat for static binaries had not been a major
> problem, e.g., gkermit on NetBSD-1.5 was only about 15% bigger than
> on NetBSD-1.2.

Is this the same version of gkermit on 1.5 and 1.2?

I'm not surprised to see the compiler slowing down. Compilers are an
excellent example of time vs space tradeoffs and so forth. If the 
newer compilers are being written to run on modern systems then perhaps
the code generator is making better code at the expense of compile-time
CPU (or something). That isn't bloat.

I'm not denying that NetBSD is bigger than 4.3BSD and perhaps slower, of
course. I'm just curious what exactly is causing the slowdowns you are
seeing.
-- 
Kevin P. Neal                                http://www.pobox.com/~kpn/
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