Hi I have setup kernel 3.3 ( which has save and restore support for PMU registers in KVM ). Also, I have started a guest machine by specifying "--cpu host" in qemu-kvm and verified that the "arch_perfmon" cpu flag is visible inside the guest. However, I could not succeed in counting the number of cpu cycles for a cpu intensive program using oprofile inside guest. The following is a simple script used to run oprofile ############################################# /usr/bin/opcontrol --reset /usr/bin/opcontrol --event="default" /usr/bin/opcontrol --setup --no-vmlinux --separate=library /usr/bin/opcontrol --start #This is a cpu intensive program ./a.out /usr/bin/opcontrol --shutdown opreport --global-percent --long-filenames --threshold 20 ############################################## Output on host CPU: Core 2, speed 2201 MHz (estimated) Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000 CPU_CLK_UNHALT...| samples| %| ------------------ 21125 43.2597 /home/shashank/workspace/seminar/code/oprofile/a.out Output on guest CPU: Core 2, speed 2200.19 MHz (estimated) Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000 CPU_CLK_UNHALT...| samples| %| ------------------ 1 100.000 /no-vmlinux Note that only 1 sample got collected on guest. I see the same behavior for other workloads on guest. Also, I executed CPUID instruction on both guest and host to check the PMU leaf details (0x0A) and found them to be the same. Please let me know if I am missing anything here. I am yet to profile the same workload on host/guest using perf. Regards, Shashank -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
