diff options
author | Nicholas Piggin <npiggin@gmail.com> | 2018-05-05 03:19:30 +1000 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-06-03 20:40:27 +1000 |
commit | 3d3a6021ddcbe9c31520e4e7b65e5ce5dc58274d (patch) | |
tree | 10d300ac9f4f3b8354b9e35075d3d5a776739e7e /arch/powerpc/kernel/time.c | |
parent | 36d632ea831fd2fa3cb62599a465825f59076f64 (diff) |
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: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/time.c')
-rw-r--r-- | arch/powerpc/kernel/time.c | 8 |
1 files changed, 0 insertions, 8 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index e7e8611e8863..1fe6a24357e7 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -597,14 +597,6 @@ static void __timer_interrupt(void) __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); } |