Should we have a test like this in the PETSc benchmark directory? Barry
Begin forwarded message: > From: Kazutomo Yoshii <kazutomo at mcs.anl.gov> > Subject: [Xlab] slow pagefault on KNC > Date: December 17, 2012 10:48:06 AM CST > To: "xlab at cels.anl.gov" <xlab at cels.anl.gov> > > Hi, > > I noticed that pagefault is very slow on KNC. It takes 850 usec > while it takes ~1 usec on Xeon, so prefaulting 1GB of memory region > takes 222 sec on KNC. > > This may not impact a big app runs for hours and hours, but I guess > this definitely affects short-lived processes or threads, which might > make MIC less fascinating. > > This could be a hardware problem(need to check Phi), a kernel bug, > or maybe sage of SMP kernel on many-core. > If this is the last case, it would be really interesting for me. > > Attached a simple page fault benchmark. > > - kaz [see attached file: pftest.c]_______________________________________________ > Xlab mailing list > Xlab at lists.cels.anl.gov > https://lists.cels.anl.gov/mailman/listinfo/xlab -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: pftest.c URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20121217/204f45af/attachment.c>
