From: Ionela Voinescu <ionela.voinescu@arm.com>
To: catalin.marinas@arm.com, will@kernel.org, sudeep.holla@arm.com
Cc: morten.rasmussen@arm.com, valentin.schneider@arm.com,
souvik.chakravarty@arm.com, viresh.kumar@linaro.org,
dietmar.eggemann@arm.com, ionela.voinescu@arm.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 2/4] arm64: wrap and generalise counter read functions
Date: Wed, 26 Aug 2020 14:03:07 +0100 [thread overview]
Message-ID: <20200826130309.28027-3-ionela.voinescu@arm.com> (raw)
In-Reply-To: <20200826130309.28027-1-ionela.voinescu@arm.com>
In preparation for other uses of Activity Monitors (AMU) cycle counters,
place counter read functionality in generic functions that can reused:
read_corecnt() and read_constcnt().
As a result, implement update_freq_counters_refs() to replace
init_cpu_freq_invariance_counters() and both initialise and update
the per-cpu reference variables.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
---
arch/arm64/kernel/cpufeature.c | 4 ++--
arch/arm64/kernel/topology.c | 36 ++++++++++++++++++++++------------
2 files changed, 26 insertions(+), 14 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 15a376689b2f..40d7a4c52558 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1522,7 +1522,7 @@ const struct cpumask *cpus_with_amu_counters(void)
}
/* Initialize the use of AMU counters for frequency invariance */
-extern void init_cpu_freq_invariance_counters(void);
+extern void update_freq_counters_refs(void);
static void cpu_amu_enable(struct arm64_cpu_capabilities const *cap)
{
@@ -1530,7 +1530,7 @@ static void cpu_amu_enable(struct arm64_cpu_capabilities const *cap)
pr_info("detected CPU%d: Activity Monitors Unit (AMU)\n",
smp_processor_id());
cpumask_set_cpu(smp_processor_id(), &amu_cpus);
- init_cpu_freq_invariance_counters();
+ update_freq_counters_refs();
}
}
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index 2ef440938282..1241087e92c8 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -121,23 +121,33 @@ int __init parse_acpi_topology(void)
}
#endif
-#ifdef CONFIG_ARM64_AMU_EXTN
+#define COUNTER_READ_STORE(NAME, VAL) \
+static inline u64 read_##NAME(void) \
+{ \
+ return VAL; \
+} \
+static inline void store_##NAME(void *val) \
+{ \
+ *(u64 *)val = read_##NAME(); \
+}
-#undef pr_fmt
-#define pr_fmt(fmt) "AMU: " fmt
+#ifdef CONFIG_ARM64_AMU_EXTN
+COUNTER_READ_STORE(corecnt, read_sysreg_s(SYS_AMEVCNTR0_CORE_EL0));
+COUNTER_READ_STORE(constcnt, read_sysreg_s(SYS_AMEVCNTR0_CONST_EL0));
+#else
+COUNTER_READ_STORE(corecnt, 0);
+COUNTER_READ_STORE(constcnt, 0);
+#endif
static DEFINE_PER_CPU_READ_MOSTLY(unsigned long, arch_max_freq_scale);
static DEFINE_PER_CPU(u64, arch_const_cycles_prev);
static DEFINE_PER_CPU(u64, arch_core_cycles_prev);
static cpumask_var_t amu_fie_cpus;
-/* Initialize counter reference per-cpu variables for the current CPU */
-void init_cpu_freq_invariance_counters(void)
+void update_freq_counters_refs(void)
{
- this_cpu_write(arch_core_cycles_prev,
- read_sysreg_s(SYS_AMEVCNTR0_CORE_EL0));
- this_cpu_write(arch_const_cycles_prev,
- read_sysreg_s(SYS_AMEVCNTR0_CONST_EL0));
+ this_cpu_write(arch_core_cycles_prev, read_corecnt());
+ this_cpu_write(arch_const_cycles_prev, read_constcnt());
}
static int validate_cpu_freq_invariance_counters(int cpu)
@@ -272,11 +282,14 @@ void topology_scale_freq_tick(void)
if (!cpumask_test_cpu(cpu, amu_fie_cpus))
return;
- const_cnt = read_sysreg_s(SYS_AMEVCNTR0_CONST_EL0);
- core_cnt = read_sysreg_s(SYS_AMEVCNTR0_CORE_EL0);
prev_const_cnt = this_cpu_read(arch_const_cycles_prev);
prev_core_cnt = this_cpu_read(arch_core_cycles_prev);
+ update_freq_counters_refs();
+
+ const_cnt = this_cpu_read(arch_const_cycles_prev);
+ core_cnt = this_cpu_read(arch_core_cycles_prev);
+
if (unlikely(core_cnt <= prev_core_cnt ||
const_cnt <= prev_const_cnt))
goto store_and_exit;
@@ -301,4 +314,3 @@ void topology_scale_freq_tick(void)
this_cpu_write(arch_core_cycles_prev, core_cnt);
this_cpu_write(arch_const_cycles_prev, const_cnt);
}
-#endif /* CONFIG_ARM64_AMU_EXTN */
--
2.17.1
next prev parent reply other threads:[~2020-08-26 13:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-26 13:03 [PATCH 0/4] arm64: cppc: add FFH support using AMUs Ionela Voinescu
2020-08-26 13:03 ` [PATCH 1/4] arm64: cpufeature: restructure AMU feedback function Ionela Voinescu
2020-08-26 13:03 ` Ionela Voinescu [this message]
2020-08-26 13:03 ` [PATCH 3/4] arm64: split counter validation function Ionela Voinescu
2020-08-26 13:03 ` [PATCH 4/4] arm64: implement CPPC FFH support using AMUs Ionela Voinescu
2020-09-11 14:40 ` Catalin Marinas
2020-09-22 16:07 ` Ionela Voinescu
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