The seemingly high rate of hardware failures on the Titans (from this
limited sample) is quite unsettling. Sure, RMAing is a possibility in some
situations. However, we have a proposal in for a GPU cluster with 64 of
these cards and this strategy is quite impractical for us. I'll be amending
our proposal and we'll go back to the trusted 680s.
Thanks to you all for your opinions!
Best,
Robert
On Tue, May 28, 2013 at 12:01:20PM -0700, Scott Le Grand wrote:
> And that's exactly the way to handle this IMO! Life is indeed too short.
>
>
>
> On Tue, May 28, 2013 at 11:42 AM, ET <sketchfoot.gmail.com> wrote:
>
> > Hi,
> >
> > I just got a superclocked Titan and one at normal freq. The first one ran
> > like a charm with no issues so far. The other standard clocked one could
> > never get past the constant pressure stage in an NPT simulation. It kept
> > writing NAN or ********* in the outfile. I swapped them about in the pcie
> > lanes then ran it solo in each one of the lanes. Despite all this it was
> > still failing the benchmark that the other one had no problems with.
> >
> > I couldn't find any memory errors with GPU-burn either, but as they cost
> > near a grand a piece, I RMA'd it today. I recommend you to do the same if
> > its not giving you any joy. Life's too short. :)
> >
> > br,
> > g
> >
> >
> > On 28 May 2013 16:57, Scott Le Grand <varelse2005.gmail.com> wrote:
> >
> > > AMBER != NAMD...
> > >
> > > GTX 680 != GTX Titan...
> > >
> > > Ian's suggestion is a good one. But even then, you need to test your
> > GPUs
> > > as the Titans are running right on the edge of stability. Like I told
> > > Marek, try running 100K iterations of Cellulose NVE twice with the same
> > > random seed. if you don't get identically bit accurate output, your GPU
> > is
> > > not working. Memtest programs do not catch this because (I am guessing)
> > > they are designed for a uniform memory hierarchy and only one path to
> > read
> > > and write data. I have a stock GTX Titan that cannot pass the Cellulose
> > > NVE test and another one that does. I spent a couple days on the former
> > > GPU looking for the imaginary bug that went away like magic the second I
> > > switched out the GPU.
> > >
> > > Scott
> > >
> > >
> > >
> > >
> > >
> > > On Tue, May 28, 2013 at 8:11 AM, Robert Konecny <rok.ucsd.edu> wrote:
> > >
> > > > Hi Scott,
> > > >
> > > > unfortunately we are seeing similar Amber instability on GTX Titans as
> > > > Marek is. We have a box with four GTX Titans (not oveclocked) running
> > > > CentOS 6.3 with NVidia 319.17 driver and Amber 12.2. Any Amber
> > simulation
> > > > longer than 10-15 min eventually crashes on these cards, including both
> > > JAC
> > > > benchmarks (with extended run time). This is reproducible on all four
> > > > cards.
> > > >
> > > > To eliminate the possible hardware error we ran extended GPU memory
> > tests
> > > > on all four Titans with memtestG80, cuda_memtest and also gpu_burn -
> > all
> > > > finished without errors. Since I agree that these programs may not test
> > > the
> > > > GPU completely we also set up simulations with NAMD. We can run four
> > NAMD
> > > > simulations simultaneously for many days without any errors on this
> > > > hardware. For reference - we also have exactly the same server with the
> > > > same hardware components but with four GTX680s and this setup works
> > just
> > > > fine for Amber. So all this leads me to believe that a hardware error
> > is
> > > > not very likely.
> > > >
> > > > I would appreciate your comments on this, perhaps there is something
> > else
> > > > causing these errors which we are not seeing.
> > > >
> > > > Thanks,
> > > >
> > > > Robert
> > > >
> > > >
> > > > On Mon, May 27, 2013 at 04:25:24PM -0700, Scott Le Grand wrote:
> > > > > I have two GTX Titans. One is defective, the other is not.
> > > > Unfortunately,
> > > > > they both pass all standard GPU memory tests.
> > > > >
> > > > > What the defective one doesn't do is generate reproducibly
> > bit-accurate
> > > > > outputs for simulations of Factor IX (90,986 atoms) or larger, of
> > 100K
> > > or
> > > > > so iterations.
> > > > >
> > > > > Which is yet another reason why I insist on MD algorithms (especially
> > > on
> > > > > GPUS) being deterministic. Besides its ability to find software
> > bugs,
> > > > and
> > > > > fulfilling one of the most important tenets of science, it's a great
> > > way
> > > > to
> > > > > diagnose defective hardware with very little effort.
> > > > >
> > > > > 928 MHz? That's 6% above the boost clock of a stock Titan. Titan is
> > > > > pushing the performance envelope as is. If you're going to pay the
> > > > premium
> > > > > for such chips, I'd send them back until you get one that runs
> > > correctly.
> > > > > I'm very curious how fast you can push one of these things before
> > they
> > > > give
> > > > > out.
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > On Mon, May 27, 2013 at 10:01 AM, Marek Maly <marek.maly.ujep.cz>
> > > wrote:
> > > > >
> > > > > > Dear all,
> > > > > >
> > > > > > I have recently bought two "EVGA GTX TITAN Superclocked" GPUs.
> > > > > >
> > > > > > I did the first calculations (pmemd.cuda in Amber12) with systems
> > > > around
> > > > > > 60K atoms without any problems (NPT, Langevin), but when I later
> > > tried
> > > > > > with bigger systems (around 100K atoms) I obtained "classical"
> > > > irritating
> > > > > > errors
> > > > > >
> > > > > > cudaMemcpy GpuBuffer::Download failed unspecified launch failure
> > > > > >
> > > > > > just after few thousands of MD steps.
> > > > > >
> > > > > > So this was obviously the reason for memtestG80 tests.
> > > > > > ( https://simtk.org/home/memtest ).
> > > > > >
> > > > > > So I compiled memtestG80 from sources ( memtestG80-1.1-src.tar.gz )
> > > and
> > > > > > then tested
> > > > > > just small part of memory GPU (200 MB) using 100 iterations.
> > > > > >
> > > > > > On both cards I have obtained huge amount of errors but "just" on
> > > > > > "Random blocks:". 0 errors in all remaining tests in all
> > iterations.
> > > > > >
> > > > > > ------THE LAST ITERATION AND FINAL RESULTS-------
> > > > > >
> > > > > > Test iteration 100 (GPU 0, 200 MiB): 169736847 errors so far
> > > > > > Moving Inversions (ones and zeros): 0 errors (6 ms)
> > > > > > Memtest86 Walking 8-bit: 0 errors (53 ms)
> > > > > > True Walking zeros (8-bit): 0 errors (26 ms)
> > > > > > True Walking ones (8-bit): 0 errors (26 ms)
> > > > > > Moving Inversions (random): 0 errors (6 ms)
> > > > > > Memtest86 Walking zeros (32-bit): 0 errors (105 ms)
> > > > > > Memtest86 Walking ones (32-bit): 0 errors (104 ms)
> > > > > > Random blocks: 1369863 errors (27 ms)
> > > > > > Memtest86 Modulo-20: 0 errors (215 ms)
> > > > > > Logic (one iteration): 0 errors (4 ms)
> > > > > > Logic (4 iterations): 0 errors (8 ms)
> > > > > > Logic (shared memory, one iteration): 0 errors (8 ms)
> > > > > > Logic (shared-memory, 4 iterations): 0 errors (25 ms)
> > > > > >
> > > > > > Final error count after 100 iterations over 200 MiB of GPU memory:
> > > > > > 171106710 errors
> > > > > >
> > > > > > ------------------------------------------
> > > > > >
> > > > > > I have some questions and would be really grateful for any
> > comments.
> > > > > >
> > > > > > Regarding overclocking, using the deviceQuery I found out that
> > under
> > > > linux
> > > > > > both cards run
> > > > > > automatically using boost shader/GPU frequency which is here 928
> > MHz
> > > > (the
> > > > > > basic value for these factory OC cards is 876 MHz). deviceQuery
> > > > reported
> > > > > > Memory Clock rate is 3004 MHz although "it" should be 6008 MHz but
> > > > maybe
> > > > > > the quantity which is reported by deviceQuery "Memory Clock rate"
> > is
> > > > > > different from the product specification "Memory Clock" . It seems
> > > that
> > > > > > "Memory Clock rate" = "Memory Clock"/2. Am I right ? Or just
> > > > deviceQuery
> > > > > > is not able to read this spec. properly
> > > > > > in Titan GPU ?
> > > > > >
> > > > > > Anyway for the moment I assume that the problem might be due to the
> > > > high
> > > > > > shader/GPU frequency.
> > > > > > (see here : http://folding.stanford.edu/English/DownloadUtils )
> > > > > >
> > > > > > To verify this hypothesis one should perhaps UNDERclock to basic
> > > > frequency
> > > > > > which is in this
> > > > > > model 876 MHz or even to the TITAN REFERENCE frequency which is 837
> > > > MHz.
> > > > > >
> > > > > > Obviously I am working with these cards under linux (CentOS
> > > > > > 2.6.32-358.6.1.el6.x86_64) and as I found, the OC tools under linux
> > > > are in
> > > > > > fact limited just to NVclock utility, which is unfortunately
> > > > > > out of date (at least speaking about the GTX Titan ). I have
> > obtained
> > > > this
> > > > > > message when I wanted
> > > > > > just to let NVclock utility to read and print shader and memory
> > > > > > frequencies of my Titan's:
> > > > > >
> > > > > > -------------------------------------------------------------------
> > > > > >
> > > > > > [root.dyn-138-272 NVCLOCK]# nvclock -s --speeds
> > > > > > Card: Unknown Nvidia card
> > > > > > Card number: 1
> > > > > > Memory clock: -2147483.750 MHz
> > > > > > GPU clock: -2147483.750 MHz
> > > > > >
> > > > > > Card: Unknown Nvidia card
> > > > > > Card number: 2
> > > > > > Memory clock: -2147483.750 MHz
> > > > > > GPU clock: -2147483.750 MHz
> > > > > >
> > > > > >
> > > > > > -------------------------------------------------------------------
> > > > > >
> > > > > >
> > > > > > I would be really grateful for some tips regarding "NVclock
> > > > alternatives",
> > > > > > but after wasting some hours with googling it seems that there is
> > no
> > > > other
> > > > > > Linux
> > > > > > tool with NVclock functionality. So the only possibility is here
> > > > perhaps
> > > > > > to edit
> > > > > > GPU bios with some Lin/DOS/Win tools like (Kepler BIOS Tweaker,
> > > > NVflash)
> > > > > > but obviously
> > > > > > I would like to rather avoid such approach as using it means
> > perhaps
> > > > also
> > > > > > to void the warranty even if I am going to underclock the GPUs not
> > to
> > > > > > overclock them.
> > > > > > So before this eventual step (GPU bios editing) I would like to
> > have
> > > > some
> > > > > > approximative estimate
> > > > > > of the probability, that the problems are here really because of
> > the
> > > > > > overclocking
> > > > > > (too high (boost) default shader frequency).
> > > > > >
> > > > > > This probability I hope to estimate from the eventual responses of
> > > > another
> > > > > > Amber/Titan SC users, if I am not the only crazy guy who bought
> > this
> > > > model
> > > > > > for Amber calculations :)) But of course any eventual experiences
> > > with
> > > > > > Titan cards related to their memtestG80 results and
> > > UNDER/OVERclocking
> > > > > > (if possible in Linux OS) are of course welcomed as well !
> > > > > >
> > > > > > My HW/SW configuration
> > > > > >
> > > > > > motherboard: ASUS P9X79 PRO
> > > > > > CPU: Intel Core i7-3930K
> > > > > > RAM: CRUCIAL Ballistix Sport 32GB (4x8GB) DDR3 1600 VLP
> > > > > > CASE: CoolerMaster Dominator CM-690 II Advanced,
> > > > > > Power:Enermax PLATIMAX EPM1200EWT 1200W, 80+, Platinum
> > > > > > GPUs : 2 x EVGA GTX TITAN Superclocked 6GB
> > > > > > cooler: Cooler Master Hyper 412 SLIM
> > > > > >
> > > > > > OS: CentOS (2.6.32-358.6.1.el6.x86_64)
> > > > > > driver version: 319.17
> > > > > > cudatoolkit_5.0.35_linux_64_rhel6.x
> > > > > >
> > > > > > The computer is in air-conditioned room with permanent external
> > > > > > temperature around 18°C
> > > > > >
> > > > > >
> > > > > > Thanks a lot in advance for any comment/experience !
> > > > > >
> > > > > > Best wishes,
> > > > > >
> > > > > > Marek
> > > > > >
> > > > > > --
> > > > > > Tato zpráva byla vytvořena převratným poštovním klientem Opery:
> > > > > > http://www.opera.com/mail/
> > > > > >
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Received on Tue May 28 2013 - 14:00:11 PDT
