Messages in this thread | | | Subject | Re: [PATCH v14 00/11] KVM: x86/pmu: Guest Last Branch Recording Enabling | From | Liuxiangdong <> | Date | Fri, 30 Jul 2021 11:15:56 +0800 |
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Hi, like.
Does it have requirement on CPU if we want to use LBR in Guest?
I have tried linux-5.14-rc3 on different CPUs. And I can use lbr on Haswell, Broadwell, skylake and icelake, but I cannot use lbr on IvyBridge.
Thanks!
On 2021/7/29 20:40, Liuxiangdong wrote: > Hi, like. > > This patch set has been merged in 5.12 kernel tree so we can use LBR > in Guest. > Does it have requirement on CPU? > I can use lbr in guest on skylake and icelake, but cannot on IvyBridge. > > I can see lbr formats(000011b) in perf_capabilities msr(0x345), but > there is still > error when I try. > > $ perf record -b > Error: > cycles: PMU Hardware doesn't support sampling/overflow-interrupts. Try > 'perf stat' > > Host CPU: > Architecture: x86_64 > CPU op-mode(s): 32-bit, 64-bit > Byte Order: Little Endian > Address sizes: 46 bits physical, 48 bits virtual > CPU(s): 24 > On-line CPU(s) list: 0-23 > Thread(s) per core: 2 > Core(s) per socket: 6 > Socket(s): 2 > NUMA node(s): 2 > Vendor ID: GenuineIntel > CPU family: 6 > Model: 62 > Model name: Intel(R) Xeon(R) CPU E5-2620 v2 @ > 2.10GHz > Stepping: 4 > > > Thanks! > Xiangdong Liu
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