Messages in this thread | | | Date | Tue, 1 Nov 2022 13:30:08 +0100 | From | Andrew Jones <> | Subject | Re: [RFC 1/9] RISC-V: Define a helper function to probe number of hardware counters |
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On Mon, Jul 18, 2022 at 10:01:57AM -0700, Atish Patra wrote: > KVM module needs to know how many hardware counters the platform supports. > Otherwise, it will not be able to show optimal value of virtual ^ the > counters to the guest. > > Signed-off-by: Atish Patra <atishp@rivosinc.com> > --- > drivers/perf/riscv_pmu_sbi.c | 23 +++++++++++++++++------ > include/linux/perf/riscv_pmu.h | 4 ++++ > 2 files changed, 21 insertions(+), 6 deletions(-) > > diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c > index 24124546844c..1723af68ffa1 100644 > --- a/drivers/perf/riscv_pmu_sbi.c > +++ b/drivers/perf/riscv_pmu_sbi.c > @@ -27,6 +27,7 @@ > */ > static union sbi_pmu_ctr_info *pmu_ctr_list; > static unsigned int riscv_pmu_irq; > +static struct riscv_pmu *rvpmu;
Do we really need rvpmu? From a quick scan of the series it's only used for num_hw_counters, which has to be added to struct riscv_pmu, and num_counters. How about instead creating a static global for num_counters and then getting num_hw_counters by iterating pmu_ctr_list. If we want riscv_pmu_sbi_get_num_hw_ctrs() to be faster, then we can cache the value in a static variable in the function.
Thanks, drew
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