diff options
Diffstat (limited to 'arch/s390/kernel/vtime.c')
| -rw-r--r-- | arch/s390/kernel/vtime.c | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c index e53d3595a7c8..c8653435c70d 100644 --- a/arch/s390/kernel/vtime.c +++ b/arch/s390/kernel/vtime.c @@ -28,6 +28,7 @@ static atomic64_t virt_timer_elapsed; static DEFINE_PER_CPU(u64, mt_cycles[32]); static DEFINE_PER_CPU(u64, mt_scaling_mult) = { 1 }; static DEFINE_PER_CPU(u64, mt_scaling_div) = { 1 }; +static DEFINE_PER_CPU(u64, mt_scaling_jiffies); static inline u64 get_vtimer(void) { @@ -85,19 +86,24 @@ static int do_account_vtime(struct task_struct *tsk, int hardirq_offset) S390_lowcore.steal_timer += S390_lowcore.last_update_clock - clock; /* Do MT utilization calculation */ - if (smp_cpu_mtid) { + if (smp_cpu_mtid && + time_after64(jiffies_64, __this_cpu_read(mt_scaling_jiffies))) { u64 cycles_new[32], *cycles_old; - u64 delta, mult, div; + u64 delta, fac, mult, div; cycles_old = this_cpu_ptr(mt_cycles); if (stcctm5(smp_cpu_mtid + 1, cycles_new) < 2) { + fac = 1; mult = div = 0; for (i = 0; i <= smp_cpu_mtid; i++) { delta = cycles_new[i] - cycles_old[i]; - mult += delta; - div += (i + 1) * delta; + div += delta; + mult *= i + 1; + mult += delta * fac; + fac *= i + 1; } - if (mult > 0) { + div *= fac; + if (div > 0) { /* Update scaling factor */ __this_cpu_write(mt_scaling_mult, mult); __this_cpu_write(mt_scaling_div, div); @@ -105,6 +111,7 @@ static int do_account_vtime(struct task_struct *tsk, int hardirq_offset) sizeof(u64) * (smp_cpu_mtid + 1)); } } + __this_cpu_write(mt_scaling_jiffies, jiffies_64); } user = S390_lowcore.user_timer - ti->user_timer; @@ -376,4 +383,11 @@ void vtime_init(void) { /* set initial cpu timer */ set_vtimer(VTIMER_MAX_SLICE); + /* Setup initial MT scaling values */ + if (smp_cpu_mtid) { + __this_cpu_write(mt_scaling_jiffies, jiffies); + __this_cpu_write(mt_scaling_mult, 1); + __this_cpu_write(mt_scaling_div, 1); + stcctm5(smp_cpu_mtid + 1, this_cpu_ptr(mt_cycles)); + } } |