On Thursday, November 18, 2010 03:55:35 pm Brice Goglin wrote: > Le 18/11/2010 08:50, Jirka Hladky a écrit : > > Hi all, > > > > Red Hat would like to included hwloc in the upcoming version of the Red > > Hat Enterprise Linux 6.1. There is Bugzilla 648593 > > [RFE] Include Portable Hardware Locality (hwloc) in RHEL > > > > https://bugzilla.redhat.com/show_bug.cgi?id=648593 > > > > to address this. > > > > I got following input from the devel: > > ================================================= > > There appears to be a significant drawback to using hwloc. The core # > > shown in hwloc-ls does NOT map 1:1 with the processor id in > > /proc/cpuinfo. > > > > For example, on intel-s3e36-02.lab hwloc shows the core ids in socket 0 > > as {0,1,2,3,4,5,6,7}. > > > > /proc/cpuinfo shows these as physically being {0,4,8,12,16,20,24,28}. > > > > On the cmd-line, hwloc-ls does indicate a difference between the hwloc > > core id and the physical id: > > > > [root@intel-s3e36-02 ~]# hwloc-ls > > Machine (64GB) > > > > NUMANode #0 (phys=0 16GB) + Socket #0 + L3 #0 (24MB) > > > > L2 #0 (256KB) + L1 #0 (32KB) + Core #0 + PU #0 (phys=0) > > L2 #1 (256KB) + L1 #1 (32KB) + Core #1 + PU #1 (phys=4) > > L2 #2 (256KB) + L1 #2 (32KB) + Core #2 + PU #2 (phys=8) > > L2 #3 (256KB) + L1 #3 (32KB) + Core #3 + PU #3 (phys=12) > > L2 #4 (256KB) + L1 #4 (32KB) + Core #4 + PU #4 (phys=16) > > L2 #5 (256KB) + L1 #5 (32KB) + Core #5 + PU #5 (phys=20) > > L2 #6 (256KB) + L1 #6 (32KB) + Core #6 + PU #6 (phys=24) > > L2 #7 (256KB) + L1 #7 (32KB) + Core #7 + PU #7 (phys=28) > > > > If you use the graphical interface, it is possible that > > customers/GSS/everyone screws up the reporting of CPU #s. > > > > Possible solution: Have hwloc-ls use '-p' by default. > > ================================================= > > > > I'm not sure if you are open to change the default from --logical to -- > > physical. Please let me know your opinion on it. If you don't think that > > it's a good idea perhaps you can give us arguments why you prefer > > logical indexing over physical indexing.
Hi Brice, > We want to keep a consistent default across the whole project. The API, > hwloc-calc and hwloc-bind use logical by default. I do agree. > > > Another point is that at the moment you cannot distinguish if the > > graphical output (.png, X, ...) was created with lstopo --physical or > > lstopo --logical. > Actually, you can. Instead of "Core #0", you get "Core p#0" (this "p" > means "physical"). Oh, you are right. I didn't notice it. For the novice user, it will be difficult to notice the difference. Actually, I had the same problem when I have first started lstopo. I was wondering how these indexes match with /proc/cpuinfo indexing. > > Could you please add the legend to the picture explaining which index was > > used? > > I guess it's possible. Oh, this would be great! Will it make it into 1.1? Jirka
