On Fri, Aug 12, 2022 at 12:05 PM Atish Patra <ati...@atishpatra.org> wrote:
>
> On Tue, Aug 2, 2022 at 4:33 PM Atish Patra <ati...@rivosinc.com> wrote:
> >
> > 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 remaining PMU infrastructure to support
> > PMU in virt machine. The first seven patches from the original series
> > have been merged already.
> >
> > 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 latest
> > OpenSBI & Linux kernel.
> >
> > Perf stat:
> > ==========
> > [root@fedora-riscv ~]# perf stat -e cycles -e instructions -e
> > dTLB-load-misses -e dTLB-store-misses -e iTLB-load-misses \
> > > perf bench sched messaging -g 1 -l 10
> > # Running 'sched/messaging' benchmark:
> > # 20 sender and receiver processes per group
> > # 1 groups == 40 processes run
> >
> > Total time: 0.265 [sec]
> >
> > Performance counter stats for 'perf bench sched messaging -g 1 -l 10':
> >
> > 4,167,825,362 cycles
> > 4,166,609,256 instructions # 1.00 insn per cycle
> > 3,092,026 dTLB-load-misses
> > 258,280 dTLB-store-misses
> > 2,068,966 iTLB-load-misses
> >
> > 0.585791767 seconds time elapsed
> >
> > 0.373802000 seconds user
> > 1.042359000 seconds sys
> >
> > Perf record:
> > ============
> > [root@fedora-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 1 -l 10
> > # Running 'sched/messaging' benchmark:
> > # 20 sender and receiver processes per group
> > # 1 groups == 40 processes run
> >
> > Total time: 1.397 [sec]
> > [ perf record: Woken up 10 times to write data ]
> > Check IO/CPU overload!
> > [ perf record: Captured and wrote 8.211 MB perf.data (214486 samples) ]
> >
> > [root@fedora-riscv riscv]# perf report
> > Available samples
> > 107K cycles
> > ◆
> > 107K instructions
> > ▒
> > 250 dTLB-load-misses
> > ▒
> > 13 dTLB-store-misses
> > ▒
> > 172 iTLB-load-misses
> > ..
> >
> > Changes from v11->v12:
> > 1. Rebased on top of the apply-next.
> > 2. Aligned the write function & .min_priv to the previous line.
> > 3. Fixed the FDT generations for multi-socket scenario.
> > 4. Dropped interrupt property from the DT.
> > 5. Generate illegal instruction fault instead of virtual instruction fault
> > for VS/VU access while mcounteren is not set.
> >
> > Changes from v10->v11:
> > 1. Rebased on top of the master where first 7 patches were already merged.
> > 2. Removed unnecessary additional check in ctr predicate function.
> > 3. Removed unnecessary priv version checks in mcountinhibit read/write.
> > 4. Added Heiko's reviewed-by/tested-by tags.
> >
> > Changes from v8->v9:
> > 1. Added the write_done flags to the vmstate.
> > 2. Fixed the hpmcounter read access from M-mode.
> >
> > Changes from v7->v8:
> > 1. Removeding ordering constraints for mhpmcounter & mhpmevent.
> >
> > Changes from v6->v7:
> > 1. Fixed all the compilation errors for the usermode.
> >
> > Changes from v5->v6:
> > 1. Fixed compilation issue with PATCH 1.
> > 2. Addressed other comments.
> >
> > Changes from v4->v5:
> > 1. Rebased on top of the -next with following patches.
> > - isa extension
> > - priv 1.12 spec
> > 2. Addressed all the comments on v4
> > 3. Removed additional isa-ext DT node in favor of riscv,isa string update
> >
> > Changes from v3->v4:
> > 1. Removed the dummy events from pmu DT node.
> > 2. Fixed pmu_avail_counters mask generation.
> > 3. Added a patch to simplify the predicate function for counters.
> >
> > 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/qemu/tree/riscv_pmu_v12
> >
> > Atish Patra (6):
> > target/riscv: Add sscofpmf extension support
> > target/riscv: Simplify counter predicate function
> > target/riscv: Add few cache related PMU events
> > hw/riscv: virt: Add PMU DT node to the device tree
> > target/riscv: Update the privilege field for sscofpmf CSRs
> > target/riscv: Remove additional priv version check for mcountinhibit
> >
> > hw/riscv/virt.c | 16 ++
> > target/riscv/cpu.c | 12 ++
> > target/riscv/cpu.h | 25 +++
> > target/riscv/cpu_bits.h | 55 +++++
> > target/riscv/cpu_helper.c | 25 +++
> > target/riscv/csr.c | 312 +++++++++++++++++-----------
> > target/riscv/machine.c | 1 +
> > target/riscv/pmu.c | 414 +++++++++++++++++++++++++++++++++++++-
> > target/riscv/pmu.h | 8 +
> > 9 files changed, 749 insertions(+), 119 deletions(-)
> >
> > --
> > 2.25.1
> >
> >
>
> Any other comments on this series ?
Sooo....
The series looks good, the patches are all reviewed, but do you mind
rebasing this on
https://github.com/alistair23/qemu/tree/riscv-to-apply.next ? Sorry
about the hassle
Alistair
>
>
> --
> Regards,
> Atish
>
