Re: BAD CPU --> SIG11
Darrin R. Smith (drsmith@eznet.net)
Fri, 24 May 1996 20:11:56 -0400
Jan Kees Joosse wrote:
>
> In article <Pine.LNX.3.93.960512232530.407C-100000@jcoy-ppp.cscwc.pima.edu>,
> "Jeff Coy Jr." <jcoy@jcoy-ppp.cscwc.pima.edu> writes:
> >On Sun, 12 May 1996, lilo wrote:
> >
> >=> There are also known irregularities with L2 writeback cache and
> >=> cleanroom-microcode AMD DX2/80's. I've never seen anything more than weird
> >=> bogomips values though....
> >=>
> >i have a 486dx2-80, and the sig 11's only showed up for me when i really
> >pushed the machine, like when i recompiled gcc. the first build would be
> >fine, but the second build would crash about 45 minutes in. the crashes
> >weren't really frequent, but setting the CPU speed back to 66mHz solved
> >the problem and offered the fastest compile time.
> >
> >the only other solution was turning off the external cache, but without
> >the extern cache, first stage gcc compile was 36 minutes at 80 mHz, but at
> >66 mHz i get 26 minute first stage builds.
>
> Take a look at http://www.bitwizard.nl/sig11/ This page describes
> causes for a signal 11 while compiling (esp. kernel-compiles).
>
> The effects of turning of the external cache also point to the direction
> of memory subsystem problems. When you set the CPU speed to 80 MHz the
> motherboard operates at 40Mhz, but when the CPU-clock is set to 66MHz the
> board operates at 33MHz. Maybe slow memory? Check waitstages.
>
> Jan Kees
Incedentally, one fix for the 80 Mhz AMD might have been to
go to Radio Shack or the local elecronics store and buy a little
tube of white silicon heatsink compound. I put a thin layer of this
between my cpu/heatsink combination and I have never had a problem
with my own AMD-80 chip. This will effectively increase the cooling
ability of the heatsink and fan by providing better contact between
the processor and heatsink. It's scary to think that most processors
just have the heatsink clipped on with only bare contact to do the
cooling.
--Darrin