Re: [libvirt] [PATCH 4/5] qemu: Build command line for NUMA tuning

于 2011年05月05日 23:21, Daniel P. Berrange 写道: >On Thu, May 05, 2011 at 05:38:29PM +0800, Osier Yang wrote: >>Just prepend numactl command line to qemu command line. >>--- >> src/qemu/qemu_command.c | 16 ++++++++++++++++ >> 1 files changed, 16 insertions(+), 0 deletions(-) >> >>diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c >>index 2205ed1..156fdfb 100644 >>--- a/src/qemu/qemu_command.c >>+++ b/src/qemu/qemu_command.c >>@@ -2762,7 +2762,23 @@ qemuBuildCommandLine(virConnectPtr conn, >> break; >> } >> >>+#ifdef HAVE_NUMACTL >>+ /* XXX: Logic here to build numactl commmand line need to be changed if >>+ * more NUMA tuning related stuffs in future. >>+ */ >>+ if (def->numatune.membind.nodeset) { >>+ cmd = virCommandNewArgList(NUMACTL, >>+ "-m", >>+ def->numatune.membind.nodeset, >>+ NULL); >>+ >>+ virCommandAddArgList(cmd, emulator, "-S", NULL); >>+ } else { >>+ cmd = virCommandNewArgList(emulator, "-S", NULL); >>+ } >>+#else >> cmd = virCommandNewArgList(emulator, "-S", NULL); >>+#endif > >NACK to this approach. We should be using the libnuma APIs to set the >memory binding for the process directly, and not running the numactl >command. Hi, Dan, I looked at libnuma API, it looks to me there is no API provided to change the NUMA policy for process with specified PID, like sched_setaffinity, think it's reasonable to not allow to set the policy with specified PID, otherwise if one change the NUMA policy for a process frequently, it will be pain for kernel. AFAIK, If one wants to use libnuma to change a process' NUMA policy, one way is to use libnuma in the codes of the program for which one want to set the policy. The other way is to use numactl.