The latest version of the SBI specification includes a Performance Monitoring Unit(PMU) extension[1] which allows the supervisor to start/stop/configure various PMU events. The Sscofpmf ('Ss' for Privileged arch and Supervisor-level extensions, and 'cofpmf' for Count OverFlow and Privilege Mode Filtering) extension[2] allows the perf like tool to handle overflow interrupts and filtering support.
This series implements full PMU infrastructure to support PMU in virt machine. This will allow us to add any PMU events in future. Currently, this series enables the following omu events. 1. cycle count 2. instruction count 3. DTLB load/store miss 4. ITLB prefetch miss The first two are computed using host ticks while last three are counted during cpu_tlb_fill. We can do both sampling and count from guest userspace. This series has been tested on both RV64 and RV32. Both Linux[3] and Opensbi[4] patches are required to get the perf working. Here is an output of perf stat/report while running hackbench with OpenSBI & Linux kernel patches applied [3]. Perf stat: ========== [root@fedora-riscv riscv]# perf stat -e r8000000000000005 -e r8000000000000007 \ -e r8000000000000006 -e r0000000000020002 -e r0000000000020004 -e branch-misses \ -e cache-misses -e dTLB-load-misses -e dTLB-store-misses -e iTLB-load-misses \ -e cycles -e instructions perf bench sched messaging -g 15 -l 10 \ Running with 15*40 (== 600) tasks. Time: 6.578 Performance counter stats for './hackbench -pipe 15 process': 1,794 r8000000000000005 (52.59%) --> SBI_PMU_FW_SET_TIMER 2,859 r8000000000000007 (60.74%) --> SBI_PMU_FW_IPI_RECVD 4,205 r8000000000000006 (68.71%) --> SBI_PMU_FW_IPI_SENT 0 r0000000000020002 (81.69%) <not counted> r0000000000020004 (0.00%) <not counted> branch-misses (0.00%) <not counted> cache-misses (0.00%) 7,878,328 dTLB-load-misses (15.60%) 680,270 dTLB-store-misses (28.45%) 8,287,931 iTLB-load-misses (39.24%) 20,008,506,675 cycles (48.60%) 21,484,427,932 instructions # 1.07 insn per cycle (56.60%) 1.681344735 seconds time elapsed 0.614460000 seconds user 8.313254000 seconds sys Perf record: ============ [root@fedora-riscv riscv]# perf record -e cycles -e instructions \ -e dTLB-load-misses -e dTLB-store-misses -e iTLB-load-misses -c 10000 \ perf bench sched messaging -g 15 -l 10 # Running 'sched/messaging' benchmark: # 20 sender and receiver processes per group # 15 groups == 600 processes run Total time: 1.261 [sec] [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.101 MB perf.data (845 samples) ] [root@fedora-riscv riscv]# perf report Available samples 407 cycles _ 407 instructions _ 18 dTLB-load-misses _ 2 dTLB-store-misses _ 11 iTLB-load-misses _ .. Changes from v2->v3: 1. Addressed all the comments on PATCH1-4. 2. Split patch1 into two separate patches. 3. Added explicit comments to explain the event types in DT node. 4. Rebased on latest Qemu. Changes from v1->v2: 1. Dropped the ACks from v1 as signficant changes happened after v1. 2. sscofpmf support. 3. A generic counter management framework. [1] https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/riscv-sbi.adoc [2] https://drive.google.com/file/d/171j4jFjIkKdj5LWcExphq4xG_2sihbfd/edit [3] https://github.com/atishp04/opensbi/tree/pmu_sscofpmf_v2 [3] https://github.com/atishp04/linux/tree/riscv_pmu_v4 [4] https://github.com/atishp04/qemu/tree/riscv_pmu_v3 Atish Patra (10): target/riscv: Fix PMU CSR predicate function target/riscv: Implement PMU CSR predicate function for target/riscv: pmu: Rename the counters extension to pmu target/riscv: pmu: Make number of counters configurable target/riscv: Implement mcountinhibit CSR target/riscv: Add support for hpmcounters/hpmevents target/riscv: Support mcycle/minstret write operation target/riscv: Add sscofpmf extension support target/riscv: Add few cache related PMU events hw/riscv: virt: Add PMU DT node to the device tree hw/riscv/virt.c | 36 ++ target/riscv/cpu.c | 14 +- target/riscv/cpu.h | 51 ++- target/riscv/cpu_bits.h | 59 +++ target/riscv/cpu_helper.c | 26 ++ target/riscv/csr.c | 827 +++++++++++++++++++++++++++++--------- target/riscv/machine.c | 30 +- target/riscv/meson.build | 1 + target/riscv/pmp.c | 1 + target/riscv/pmu.c | 434 ++++++++++++++++++++ target/riscv/pmu.h | 37 ++ 11 files changed, 1332 insertions(+), 184 deletions(-) create mode 100644 target/riscv/pmu.c create mode 100644 target/riscv/pmu.h -- 2.31.1