Hi David, On Tue, Sep 01, 2009 at 11:37:05PM -0700, David Rientjes wrote: > On Wed, 2 Sep 2009, Ankita Garg wrote: > > > Hi, > > > > Below is a patch to fix a couple of issues with fake numa node creation > > on ppc: > > > > 1) Presently, fake nodes could be created such that real numa node > > boundaries are not respected. So a node could have lmbs that belong to > > different real nodes. > > > > On x86_64, we can use numa=off to completely disable NUMA so that all > memory and all cpus are mapped to a single node 0. That's an extreme > example of the above and is totally permissible. > > > 2) The cpu association is broken. On a JS22 blade for example, which is > > a 2-node numa machine, I get the following: > > > > # cat /proc/cmdline > > root=/dev/sda6 numa=fake=2G,4G,,6G,8G,10G,12G,14G,16G > > # cat /sys/devices/system/node/node0/cpulist > > 0-3 > > # cat /sys/devices/system/node/node1/cpulist > > 4-7 > > # cat /sys/devices/system/node/node4/cpulist > > > > # > > > > This doesn't show what the true NUMA topology of the machine is, could you > please post the output of > > $ cat /sys/devices/system/node/node*/cpulist > $ cat /sys/devices/system/node/node*/distance > $ ls -d /sys/devices/system/node/node*/cpu[0-8] > > from a normal boot without any numa=fake? >
Heres the output as requested by you: # ls /sys/devices/system/node/ has_cpu has_normal_memory node0 node1 online possible # cat /sys/devices/system/node/node*/cpulist 0-3 4-7 # cat /sys/devices/system/node/node*/distance 10 20 20 10 # ls -d /sys/devices/system/node/node*/cpu[0-8] /sys/devices/system/node/node0/cpu0 /sys/devices/system/node/node0/cpu3 /sys/devices/system/node/node1/cpu6 /sys/devices/system/node/node0/cpu1 /sys/devices/system/node/node1/cpu4 /sys/devices/system/node/node1/cpu7 /sys/devices/system/node/node0/cpu2 /sys/devices/system/node/node1/cpu5 > > So, though the cpus 4-7 should have been associated with node4, they > > still belong to node1. The patch works by recording a real numa node > > boundary and incrementing the fake node count. At the same time, a > > mapping is stored from the real numa node to the first fake node that > > gets created on it. > > > > If there are multiple fake nodes on a real physical node, all cpus in that > node should appear in the cpulist for each fake node for which it has > local distance. Currently, the behavior of fake numa is not so on x86 as well? Below is a sample output from a single node x86 system booted with numa=fake=8: # cat node0/cpulist # cat node1/cpulist ... # cat node6/cpulist # cat node7/cpulist 0-7 Presently, just fixing the cpu association issue with ppc, as explained in my previous mail. -- Regards, Ankita Garg (ank...@in.ibm.com) Linux Technology Center IBM India Systems & Technology Labs, Bangalore, India _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
