On 02/10/2017 09:11 AM, Peter Maydell wrote: > On 10 February 2017 at 15:00, Peter Maydell <peter.mayd...@linaro.org> wrote: >> On 7 February 2017 at 21:49, Wei Huang <w...@redhat.com> wrote: >>> QEMU has implemented cycle count support for guest VM under TCG mode. >>> But this feature is not complete. In fact using perf inside a >>> 64-bit Linux guest VM (under TCG) can cause the following kernel panic >>> because some PMU registers are not implemented. >>> >>> [ 329.445970] [<fffffe000009e600>] armv8pmu_enable_event+0x58/0x8c >>> [ 329.446713] [<fffffe0000621e74>] armpmu_start+0x4c/0x74 >>> >>> This patchset solves the problem by adding support for missing vPMU >>> registers. Basic perf test can work (both ACPI and DT) now under TCG >>> by applying this patchset. >>> >>> address@hidden ~]# perf stat ls >>> Performance counter stats for 'ls': >>> >>> 226.740256 task-clock (msec) # 0.312 CPUs utilized >>> 76 context-switches # 0.335 K/sec >>> 0 cpu-migrations # 0.000 K/sec >>> 64 page-faults # 0.282 K/sec >>> 186,031,410 cycles # 0.820 GHz >>> (36.40%) >>> <not supported> stalled-cycles-frontend >>> <not supported> stalled-cycles-backend >>> <not counted> instructions (0.00%) >>> <not supported> branches >>> <not counted> branch-misses (0.00%) >>> >>> V2->V3: >>> * Remove PMXEVCNTR_EL0 support >>> * Add read access support for PMXEVTYPER and change the CONSTRAINED >>> UNPREDICTABLE behavior of PMXEVTYPER to RAZ/WI. >>> >>> V1->V2: >>> * Change most PMU registers to 64bit and the behavior of PMXEVTYPER >>> * Add support for PMXEVCNTR_EL0 >>> * Misc fixes (DT, ID_AA64DFR0_EL1, ...) under TCG mod >> >> Applied to target-arm.next, thanks. > > ...though patch 1 breaks compilation of linux-user targets. I've > fixed it up by moving the #ifndef CONFIG_USER_ONLY to the right > place to cover the new regdefs.
My bad. I normally did compilation for all targets + "make check" before sending patches out. But on that particular machine, qemu was configured for aarch64-softmmu only, thus missing this compilation error ... > > thanks > -- PMM >
