Running GMP on Ryzen

[Vincent Diepeveen]

Thanks for the update!
Much appreciated information.

That's pretty bad for AMD. Already burning 180 watt TDP on Ryzen and then 
not able to run stable that's end of business normal spoken. End of 
Trading for sure.

Vincent

On Fri, 11 Aug 2017, Torbjörn Granlund wrote:

> The GMP Ryzen dev system is now powered off, and we plan no more
> development work for Ryzen.
>
> Ryzen systems keep crashing due to serious silicon bugs:
>
> 1. When running an OS on the raw hardware, processes get spurious segfaults
>   under load.
>
> 2. When virtualising the system with Xen, the entire machine dies under
>   load.
>
> AMD apparently has decided to pretend their early Ryzen works fine except
> for GNU/Linux.  They replace CPUs on a case-by-case basis only.  But the
> only reasonable action would be to publicly confess that their early chips
> did not work properly, and make a full recall.
>
> There is a long thread about the bug (1) here:
> https://community.amd.com/thread/215773?start=0
>
> AMD people replied in the beginning, and introduced the newspeak term
> "performance marginality problem".  Later AMD decided to ignore the thread.
>
> If you're the owner of a Ryzen system and care about it working properly
> for compiling and running code, please try the following script.  Fill out
> paths within [] first and set the seq argument to the number of threads
> available.  Then look for accumulating strings ERROR in the files log.* in
> $tmpdir.
>
> On our 4 core/8 thread Ryzen, I get about 2 compilation crashes per hour
> and about 5 test suite crashes per day.  YMMV.  I've been told that newer
> Ryzen chips has a fix for bug (1).  Not sure about bug (2).
>
> #! /bin/sh
> tmpdir=/var/tmp/[somename]
> gmpsrc=[fill in this]
> mkdir $tmpdir
> cd $tmpdir || exit 1
> while true
>  do
>    for i in $(seq 16)
>      do
>        (rm -rf $i
>         mkdir $i
>         cd $i
>         $gmpsrc/configure && make && make check
>         stat=$?
>         if [ $stat != 0 ]
>           then
>             echo "ERROR exit $stat"
>           fi
>        ) &>>log.$i &
>      done
>  done
>
>
> -- 
> Torbjörn
> Please encrypt, key id 0xC8601622
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