diff options
Diffstat (limited to 'arch/s390/kernel/vtime.c')
-rw-r--r-- | arch/s390/kernel/vtime.c | 62 |
1 files changed, 37 insertions, 25 deletions
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c index b9ce650..dafc44f 100644 --- a/arch/s390/kernel/vtime.c +++ b/arch/s390/kernel/vtime.c @@ -25,7 +25,7 @@ static DEFINE_SPINLOCK(virt_timer_lock); static atomic64_t virt_timer_current; static atomic64_t virt_timer_elapsed; -static DEFINE_PER_CPU(u64, mt_cycles[32]); +DEFINE_PER_CPU(u64, mt_cycles[8]); 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); @@ -60,6 +60,34 @@ static inline int virt_timer_forward(u64 elapsed) return elapsed >= atomic64_read(&virt_timer_current); } +static void update_mt_scaling(void) +{ + u64 cycles_new[8], *cycles_old; + u64 delta, fac, mult, div; + int i; + + stcctm5(smp_cpu_mtid + 1, cycles_new); + cycles_old = this_cpu_ptr(mt_cycles); + fac = 1; + mult = div = 0; + for (i = 0; i <= smp_cpu_mtid; i++) { + delta = cycles_new[i] - cycles_old[i]; + div += delta; + mult *= i + 1; + mult += delta * fac; + fac *= i + 1; + } + div *= fac; + if (div > 0) { + /* Update scaling factor */ + __this_cpu_write(mt_scaling_mult, mult); + __this_cpu_write(mt_scaling_div, div); + memcpy(cycles_old, cycles_new, + sizeof(u64) * (smp_cpu_mtid + 1)); + } + __this_cpu_write(mt_scaling_jiffies, jiffies_64); +} + /* * Update process times based on virtual cpu times stored by entry.S * to the lowcore fields user_timer, system_timer & steal_clock. @@ -69,7 +97,6 @@ static int do_account_vtime(struct task_struct *tsk, int hardirq_offset) struct thread_info *ti = task_thread_info(tsk); u64 timer, clock, user, system, steal; u64 user_scaled, system_scaled; - int i; timer = S390_lowcore.last_update_timer; clock = S390_lowcore.last_update_clock; @@ -85,30 +112,10 @@ static int do_account_vtime(struct task_struct *tsk, int hardirq_offset) S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer; S390_lowcore.steal_timer += S390_lowcore.last_update_clock - clock; - /* Do MT utilization calculation */ + /* Update MT utilization calculation */ if (smp_cpu_mtid && - time_after64(jiffies_64, __this_cpu_read(mt_scaling_jiffies))) { - u64 cycles_new[32], *cycles_old; - u64 delta, mult, div; - - cycles_old = this_cpu_ptr(mt_cycles); - if (stcctm5(smp_cpu_mtid + 1, cycles_new) < 2) { - mult = div = 0; - for (i = 0; i <= smp_cpu_mtid; i++) { - delta = cycles_new[i] - cycles_old[i]; - mult += delta; - div += (i + 1) * delta; - } - if (mult > 0) { - /* Update scaling factor */ - __this_cpu_write(mt_scaling_mult, mult); - __this_cpu_write(mt_scaling_div, div); - memcpy(cycles_old, cycles_new, - sizeof(u64) * (smp_cpu_mtid + 1)); - } - } - __this_cpu_write(mt_scaling_jiffies, jiffies_64); - } + time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies))) + update_mt_scaling(); user = S390_lowcore.user_timer - ti->user_timer; S390_lowcore.steal_timer -= user; @@ -177,6 +184,11 @@ void vtime_account_irq_enter(struct task_struct *tsk) S390_lowcore.last_update_timer = get_vtimer(); S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer; + /* Update MT utilization calculation */ + if (smp_cpu_mtid && + time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies))) + update_mt_scaling(); + system = S390_lowcore.system_timer - ti->system_timer; S390_lowcore.steal_timer -= system; ti->system_timer = S390_lowcore.system_timer; |