Re: [Beowulf] nVidia revealed as evil

2018-01-07 Thread Lux, Jim (337K)
That will solve the cluster cooling situation, at least for a while. One just has to run appropriate ducting. From: Beowulf on behalf of "beowulf@beowulf.org" Reply-To: John Hearns Date: Saturday, January 6, 2018 at 1:13 AM To: Tim Cutts Cc: Lawrence Stewart , "beowulf@beowulf.org" Subject

Re: [Beowulf] [upgrade strategy] Intel CPU design bug & security flaw - kernel fix imposes performance penalty

2018-01-07 Thread Jörg Saßmannshausen
Dear all, Chris is right here. It depends on what is running on your HPC cluster. You might not see a performance degrade at all, or you might see one of 30% (just to stick with that number). Also, if you got a cluster which is solely used by one research group the chances they are hacking each

Re: [Beowulf] [upgrade strategy] Intel CPU design bug & security flaw - kernel fix imposes performance penalty

2018-01-07 Thread Christopher Samuel
On 08/01/18 09:18, Richard Walsh wrote: Mmm ... maybe I am missing something, but for an HPC cluster-specific solution ... how about skipping the fixes, and simply requiring all compute node jobs to run in exclusive mode and then zero-ing out user memory between jobs ... ?? If you are running

Re: [Beowulf] [upgrade strategy] Intel CPU design bug & security flaw - kernel fix imposes performance penalty

2018-01-07 Thread Richard Walsh
All, Mmm ... maybe I am missing something, but for an HPC cluster-specific solution ... how about skipping the fixes, and simply requiring all compute node jobs to run in exclusive mode and then zero-ing out user memory between jobs ... ?? Individual job performance would be preserved, while

Re: [Beowulf] [upgrade strategy] Intel CPU design bug & security flaw - kernel fix imposes performance penalty

2018-01-07 Thread Christopher Samuel
On 07/01/18 23:22, Jörg Saßmannshausen wrote: the first court cases against Intel have been filed: These would have to be Meldown related then, given that Spectre is so widely applicable. Greg K-H has a useful post up about the state of play with the various Linux kernel patches for mainline

Re: [Beowulf] [upgrade strategy] Intel CPU design bug & security flaw - kernel fix imposes performance penalty

2018-01-07 Thread Tim Cutts
It seems fairly clear to me that any processor which performs speculative execution will be vulnerable to timing attacks of this nature. I was pointed to a very much simplified but very clear explanation of this in a blog post by Eben Upton (of Raspberry Pi fame): https://www.raspberrypi.org/bl

Re: [Beowulf] Variable precision arithmetic

2018-01-07 Thread Nathan Moore
Is GMP vectorized for CUDA? https://gmplib.org/ On Sat, Jan 6, 2018 at 3:16 AM, John Hearns via Beowulf wrote: > I did not want to hijack the thread on Nvidia cards. > > Doug Eadline as usual makes a very relevant point: > "BTW, I find it interesting one of the most popular codes run > on Nvidi

Re: [Beowulf] [upgrade strategy] Intel CPU design bug & security flaw - kernel fix imposes performance penalty

2018-01-07 Thread Jörg Saßmannshausen
Dear Chris, the first court cases against Intel have been filed: http://www.spiegel.de/netzwelt/web/spectre-meltdown-erste-us-verbraucher-verklagen-intel-wegen-chip-schwachstelle-a-1186595.html http://docs.dpaq.de/13109-show_temp.pl-27.pdf http://docs.dpaq.de/13111-show_temp.pl-28.pdf http://d