Commit 3d3a6021 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman

powerpc/pseries: lparcfg calculate PURR on demand

For SPLPAR, lparcfg provides a sum of PURR registers for all CPUs.
Currently this is done by reading PURR in context switch and timer
interrupt, and storing that into a per-CPU variable. These are summed
to provide the value.

This does not work with all timer schemes (e.g., NO_HZ_FULL), and it
is sub-optimal for performance because it reads the PURR register on
every context switch, although that's been difficult to distinguish
from noise in the contxt_switch microbenchmark.

This patch implements the sum by calling a function on each CPU, to
read and add PURR values of each CPU.
Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 36d632ea
...@@ -196,14 +196,6 @@ extern u64 mulhdu(u64, u64); ...@@ -196,14 +196,6 @@ extern u64 mulhdu(u64, u64);
extern void div128_by_32(u64 dividend_high, u64 dividend_low, extern void div128_by_32(u64 dividend_high, u64 dividend_low,
unsigned divisor, struct div_result *dr); unsigned divisor, struct div_result *dr);
/* Used to store Processor Utilization register (purr) values */
struct cpu_usage {
u64 current_tb; /* Holds the current purr register values */
};
DECLARE_PER_CPU(struct cpu_usage, cpu_usage_array);
extern void secondary_cpu_time_init(void); extern void secondary_cpu_time_init(void);
extern void __init time_init(void); extern void __init time_init(void);
......
...@@ -846,10 +846,6 @@ bool ppc_breakpoint_available(void) ...@@ -846,10 +846,6 @@ bool ppc_breakpoint_available(void)
} }
EXPORT_SYMBOL_GPL(ppc_breakpoint_available); EXPORT_SYMBOL_GPL(ppc_breakpoint_available);
#ifdef CONFIG_PPC64
DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
#endif
static inline bool hw_brk_match(struct arch_hw_breakpoint *a, static inline bool hw_brk_match(struct arch_hw_breakpoint *a,
struct arch_hw_breakpoint *b) struct arch_hw_breakpoint *b)
{ {
...@@ -1182,16 +1178,6 @@ struct task_struct *__switch_to(struct task_struct *prev, ...@@ -1182,16 +1178,6 @@ struct task_struct *__switch_to(struct task_struct *prev,
WARN_ON(!irqs_disabled()); WARN_ON(!irqs_disabled());
#ifdef CONFIG_PPC64
/*
* Collect processor utilization data per process
*/
if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
struct cpu_usage *cu = this_cpu_ptr(&cpu_usage_array);
cu->current_tb = mfspr(SPRN_PURR);
}
#endif /* CONFIG_PPC64 */
#ifdef CONFIG_PPC_BOOK3S_64 #ifdef CONFIG_PPC_BOOK3S_64
batch = this_cpu_ptr(&ppc64_tlb_batch); batch = this_cpu_ptr(&ppc64_tlb_batch);
if (batch->active) { if (batch->active) {
......
...@@ -597,14 +597,6 @@ static void __timer_interrupt(void) ...@@ -597,14 +597,6 @@ static void __timer_interrupt(void)
__this_cpu_inc(irq_stat.timer_irqs_others); __this_cpu_inc(irq_stat.timer_irqs_others);
} }
#ifdef CONFIG_PPC64
/* collect purr register values often, for accurate calculations */
if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
struct cpu_usage *cu = this_cpu_ptr(&cpu_usage_array);
cu->current_tb = mfspr(SPRN_PURR);
}
#endif
trace_timer_interrupt_exit(regs); trace_timer_interrupt_exit(regs);
} }
......
...@@ -52,18 +52,20 @@ ...@@ -52,18 +52,20 @@
* Track sum of all purrs across all processors. This is used to further * Track sum of all purrs across all processors. This is used to further
* calculate usage values by different applications * calculate usage values by different applications
*/ */
static void cpu_get_purr(void *arg)
{
atomic64_t *sum = arg;
atomic64_add(mfspr(SPRN_PURR), sum);
}
static unsigned long get_purr(void) static unsigned long get_purr(void)
{ {
unsigned long sum_purr = 0; atomic64_t purr = ATOMIC64_INIT(0);
int cpu;
for_each_possible_cpu(cpu) { on_each_cpu(cpu_get_purr, &purr, 1);
struct cpu_usage *cu;
cu = &per_cpu(cpu_usage_array, cpu); return atomic64_read(&purr);
sum_purr += cu->current_tb;
}
return sum_purr;
} }
/* /*
......
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