thank you very much Mark and Szilard! ________________________________________ From: gromacs.org_gmx-users-boun...@maillist.sys.kth.se <gromacs.org_gmx-users-boun...@maillist.sys.kth.se> on behalf of Szilárd Páll <pall.szil...@gmail.com> Sent: 29 March 2017 10:09:05 To: Discussion list for GROMACS users Subject: Re: [gmx-users] importance of nvlink in GPU nodes?
Note that while, as Mark said, GPU-to-GPU NVLink is not used optimized for, when NVLink is the main CPU-to-GPU interconnect, GROMACS will certainly transfer data across it! Currently only IBM Minsky systems have direct CPU-to-GPU NVLink; on these transfers are ~3x faster than on PCI-E-based systems. While transfers generally don't take much time, given that the P100 GPUs are in general ~2.5x faster than previous generation, with PCI-E the relative time spent in transfers will increase quite significantly. So to answer the original question: the CPU-to-GPU NVLink can have a slight impact on performance, but I'd expect that to be at most 10%, typically less. Cheers, -- Szilárd On Wed, Mar 29, 2017 at 2:46 PM, Mark Abraham <mark.j.abra...@gmail.com> wrote: > Hi, > > There's no use made of NVLINK in GROMACS. The 2018 release might make some > use of it. > > Mark > > On Wed, Mar 29, 2017 at 4:19 AM Christopher Neale < > chris.ne...@alum.utoronto.ca> wrote: > > > Dear users: > > > > does anybody know if the presence of either CPU-to-GPU or GPU-to-GPU > > nvlink affects the performance or efficiency of gromacs? > > > > Thank you, > > Chris. > > -- > > Gromacs Users mailing list > > > > * Please search the archive at > > http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before > > posting! > > > > * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists > > > > * For (un)subscribe requests visit > > https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or > > send a mail to gmx-users-requ...@gromacs.org. > > > -- > Gromacs Users mailing list > > * Please search the archive at http://www.gromacs.org/Support > /Mailing_Lists/GMX-Users_List before posting! > > * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists > > * For (un)subscribe requests visit > https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or > send a mail to gmx-users-requ...@gromacs.org. > -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org. -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.