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author | Ionela Voinescu <ionela.voinescu@arm.com> | 2020-11-06 12:53:33 +0000 |
---|---|---|
committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-11-13 20:05:10 +0000 |
commit | bc3b6562a1acc1f43ae84c7d69428cdd8ae1390e (patch) | |
tree | 07f11653b60d4a32efb963a0f8225eec348abc0b | |
parent | 4b9cf23c179a27659a95c094ace658bb92f146e5 (diff) | |
download | linux-bc3b6562a1acc1f43ae84c7d69428cdd8ae1390e.tar.bz2 |
arm64: split counter validation function
In order for the counter validation function to be reused, split
validate_cpu_freq_invariance_counters() into:
- freq_counters_valid(cpu) - check cpu for valid cycle counters
- freq_inv_set_max_ratio(int cpu, u64 max_rate, u64 ref_rate) -
generic function that sets the normalization ratio used by
topology_scale_freq_tick()
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201106125334.21570-3-ionela.voinescu@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
-rw-r--r-- | arch/arm64/kernel/topology.c | 44 |
1 files changed, 26 insertions, 18 deletions
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 03f4882362ce..b8cb16e3a2cc 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -145,45 +145,49 @@ void update_freq_counters_refs(void) this_cpu_write(arch_const_cycles_prev, read_constcnt()); } -static int validate_cpu_freq_invariance_counters(int cpu) +static inline bool freq_counters_valid(int cpu) { - u64 max_freq_hz, ratio; - if (!cpu_has_amu_feat(cpu)) { pr_debug("CPU%d: counters are not supported.\n", cpu); - return -EINVAL; + return false; } if (unlikely(!per_cpu(arch_const_cycles_prev, cpu) || !per_cpu(arch_core_cycles_prev, cpu))) { pr_debug("CPU%d: cycle counters are not enabled.\n", cpu); - return -EINVAL; + return false; } - /* Convert maximum frequency from KHz to Hz and validate */ - max_freq_hz = cpufreq_get_hw_max_freq(cpu) * 1000; - if (unlikely(!max_freq_hz)) { - pr_debug("CPU%d: invalid maximum frequency.\n", cpu); + return true; +} + +static int freq_inv_set_max_ratio(int cpu, u64 max_rate, u64 ref_rate) +{ + u64 ratio; + + if (unlikely(!max_rate || !ref_rate)) { + pr_debug("CPU%d: invalid maximum or reference frequency.\n", + cpu); return -EINVAL; } /* * Pre-compute the fixed ratio between the frequency of the constant - * counter and the maximum frequency of the CPU. + * reference counter and the maximum frequency of the CPU. * - * const_freq - * arch_max_freq_scale = ---------------- * SCHED_CAPACITY_SCALE² - * cpuinfo_max_freq + * ref_rate + * arch_max_freq_scale = ---------- * SCHED_CAPACITY_SCALE² + * max_rate * * We use a factor of 2 * SCHED_CAPACITY_SHIFT -> SCHED_CAPACITY_SCALE² * in order to ensure a good resolution for arch_max_freq_scale for - * very low arch timer frequencies (down to the KHz range which should + * very low reference frequencies (down to the KHz range which should * be unlikely). */ - ratio = (u64)arch_timer_get_rate() << (2 * SCHED_CAPACITY_SHIFT); - ratio = div64_u64(ratio, max_freq_hz); + ratio = ref_rate << (2 * SCHED_CAPACITY_SHIFT); + ratio = div64_u64(ratio, max_rate); if (!ratio) { - WARN_ONCE(1, "System timer frequency too low.\n"); + WARN_ONCE(1, "Reference frequency too low.\n"); return -EINVAL; } @@ -230,8 +234,12 @@ static int __init init_amu_fie(void) } for_each_present_cpu(cpu) { - if (validate_cpu_freq_invariance_counters(cpu)) + if (!freq_counters_valid(cpu) || + freq_inv_set_max_ratio(cpu, + cpufreq_get_hw_max_freq(cpu) * 1000, + arch_timer_get_rate())) continue; + cpumask_set_cpu(cpu, valid_cpus); have_policy |= enable_policy_freq_counters(cpu, valid_cpus); } |