Sender: w00t AT recom1 DOT recom DOT com
Message-ID: <378A92DF.B1EC2B3B@recomnet.net>
Date: Mon, 12 Jul 1999 21:14:07 -0400
From: Dan Melomedman <danm AT recomnet DOT net>
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To: pgcc AT delorie DOT com
Subject: Re: Kernel Optimization and RH 6
References: <026d01beccbd$15d8d650$1687eaa8 AT infovia DOT com DOT gt>
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Reply-To: pgcc AT delorie DOT com

Rolando López wrote:

> Are the lines below the best option to compile a 2.2.x kernel with egcs/pgcc running
> on a Pentium II?
>
> -O6 -mpentiumpro -march=pentiumpro -malign-function=2
> -malign-jumps=2 -malign-loops=2 -fomit-frame-pointer
> -fstrength-reduce
>
> Background
>
> We have recently installed RedHat 6 on a PowerEdge 4300, PII 350Mhz with 256MB
> of RAM.  RedHat 6 determines the type of processor and installs the compiled
> kernel accordingly.  This kernel has been compiled with the "best" performance
> optimizations depending on the hardware.
>
> As a non-scientific measure of this kernel performance, at boot time, the
> RAID 5 routines reached 850MB/s.  This measure can be seen after booting in /var/log/messages
>
> After that, we updated the kernel to version 2.2.7, but we obtained only 835MB/s
> in the same measure.
>
> These are the options used and the compiler version:
>
> Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/egcs-2.91.66/specs
> gcc version egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)
>
> We modify /usr/src/linux/Makefile like this:
>
> HOSTCC = egcs
> HOSTCFLAGS = -Wall -Wstrict-prototypes -O6 -fomit-frame-pointer
> CC = $(CROSS_COMPILE)egcs -D__KERNEL__ -I$(HPATH)
>
> And /usr/src/linux/arch/i386 as the following:
>
> CFLAGS_NSR := -fstrength-reduce
> ifdef CONFIG_M686
> CFLAGS := $(CFLAGS) -mpentiumpro -march=pentiumpro -malign-loops=2
> -malign-jumps=2 -malign-functions=2 -DCPU=686
> endif
>
> The machine is used as transparent proxy server with squid 2.2.stable3 (compiled
> with the same options)
>
> We didn't have any trouble at compilation time nor we had stability problems
> with egcs.  Squid is reaching the 50% Hit Ratio but is using too much CPU time,
> around 27% with 17% of system time and 10% of user time.
>

The best thing to do in such situations is to get parts and build the machine yourself. Saves
money and it is what you really want instead of somebody's proprietary solution. Only takes
half-hour too. You could have had a dual Celeron machine for the money you paid for poweredge.