From 42c4ab41a176ee784c0f28c0b29025a8fc34f05a Mon Sep 17 00:00:00 2001 From: Stanislaw Gruszka Date: Wed, 29 Jul 2009 12:15:26 +0200 Subject: itimers: Merge ITIMER_VIRT and ITIMER_PROF Both cpu itimers have same data flow in the few places, this patch make unification of code related with VIRT and PROF itimers. Signed-off-by: Stanislaw Gruszka Acked-by: Peter Zijlstra Acked-by: Thomas Gleixner Cc: Oleg Nesterov Cc: Andrew Morton Cc: Paul Mackerras Cc: Benjamin Herrenschmidt LKML-Reference: <1248862529-6063-2-git-send-email-sgruszka@redhat.com> Signed-off-by: Ingo Molnar --- kernel/fork.c | 9 +-- kernel/itimer.c | 146 +++++++++++++++++++++------------------------- kernel/posix-cpu-timers.c | 98 +++++++++++++++---------------- 3 files changed, 119 insertions(+), 134 deletions(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index 29b532e718f..893ab0bf5e3 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -62,6 +62,7 @@ #include #include #include +#include #include #include @@ -790,10 +791,10 @@ static void posix_cpu_timers_init_group(struct signal_struct *sig) thread_group_cputime_init(sig); /* Expiration times and increments. */ - sig->it_virt_expires = cputime_zero; - sig->it_virt_incr = cputime_zero; - sig->it_prof_expires = cputime_zero; - sig->it_prof_incr = cputime_zero; + sig->it[CPUCLOCK_PROF].expires = cputime_zero; + sig->it[CPUCLOCK_PROF].incr = cputime_zero; + sig->it[CPUCLOCK_VIRT].expires = cputime_zero; + sig->it[CPUCLOCK_VIRT].incr = cputime_zero; /* Cached expiration times. */ sig->cputime_expires.prof_exp = cputime_zero; diff --git a/kernel/itimer.c b/kernel/itimer.c index 58762f7077e..852c88ddd1f 100644 --- a/kernel/itimer.c +++ b/kernel/itimer.c @@ -41,10 +41,43 @@ static struct timeval itimer_get_remtime(struct hrtimer *timer) return ktime_to_timeval(rem); } +static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, + struct itimerval *value) +{ + cputime_t cval, cinterval; + struct cpu_itimer *it = &tsk->signal->it[clock_id]; + + spin_lock_irq(&tsk->sighand->siglock); + + cval = it->expires; + cinterval = it->incr; + if (!cputime_eq(cval, cputime_zero)) { + struct task_cputime cputime; + cputime_t t; + + thread_group_cputimer(tsk, &cputime); + if (clock_id == CPUCLOCK_PROF) + t = cputime_add(cputime.utime, cputime.stime); + else + /* CPUCLOCK_VIRT */ + t = cputime.utime; + + if (cputime_le(cval, t)) + /* about to fire */ + cval = jiffies_to_cputime(1); + else + cval = cputime_sub(cval, t); + } + + spin_unlock_irq(&tsk->sighand->siglock); + + cputime_to_timeval(cval, &value->it_value); + cputime_to_timeval(cinterval, &value->it_interval); +} + int do_getitimer(int which, struct itimerval *value) { struct task_struct *tsk = current; - cputime_t cinterval, cval; switch (which) { case ITIMER_REAL: @@ -55,44 +88,10 @@ int do_getitimer(int which, struct itimerval *value) spin_unlock_irq(&tsk->sighand->siglock); break; case ITIMER_VIRTUAL: - spin_lock_irq(&tsk->sighand->siglock); - cval = tsk->signal->it_virt_expires; - cinterval = tsk->signal->it_virt_incr; - if (!cputime_eq(cval, cputime_zero)) { - struct task_cputime cputime; - cputime_t utime; - - thread_group_cputimer(tsk, &cputime); - utime = cputime.utime; - if (cputime_le(cval, utime)) { /* about to fire */ - cval = jiffies_to_cputime(1); - } else { - cval = cputime_sub(cval, utime); - } - } - spin_unlock_irq(&tsk->sighand->siglock); - cputime_to_timeval(cval, &value->it_value); - cputime_to_timeval(cinterval, &value->it_interval); + get_cpu_itimer(tsk, CPUCLOCK_VIRT, value); break; case ITIMER_PROF: - spin_lock_irq(&tsk->sighand->siglock); - cval = tsk->signal->it_prof_expires; - cinterval = tsk->signal->it_prof_incr; - if (!cputime_eq(cval, cputime_zero)) { - struct task_cputime times; - cputime_t ptime; - - thread_group_cputimer(tsk, ×); - ptime = cputime_add(times.utime, times.stime); - if (cputime_le(cval, ptime)) { /* about to fire */ - cval = jiffies_to_cputime(1); - } else { - cval = cputime_sub(cval, ptime); - } - } - spin_unlock_irq(&tsk->sighand->siglock); - cputime_to_timeval(cval, &value->it_value); - cputime_to_timeval(cinterval, &value->it_interval); + get_cpu_itimer(tsk, CPUCLOCK_PROF, value); break; default: return(-EINVAL); @@ -128,6 +127,36 @@ enum hrtimer_restart it_real_fn(struct hrtimer *timer) return HRTIMER_NORESTART; } +static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, + struct itimerval *value, struct itimerval *ovalue) +{ + cputime_t cval, cinterval, nval, ninterval; + struct cpu_itimer *it = &tsk->signal->it[clock_id]; + + nval = timeval_to_cputime(&value->it_value); + ninterval = timeval_to_cputime(&value->it_interval); + + spin_lock_irq(&tsk->sighand->siglock); + + cval = it->expires; + cinterval = it->incr; + if (!cputime_eq(cval, cputime_zero) || + !cputime_eq(nval, cputime_zero)) { + if (cputime_gt(nval, cputime_zero)) + nval = cputime_add(nval, jiffies_to_cputime(1)); + set_process_cpu_timer(tsk, clock_id, &nval, &cval); + } + it->expires = nval; + it->incr = ninterval; + + spin_unlock_irq(&tsk->sighand->siglock); + + if (ovalue) { + cputime_to_timeval(cval, &ovalue->it_value); + cputime_to_timeval(cinterval, &ovalue->it_interval); + } +} + /* * Returns true if the timeval is in canonical form */ @@ -139,7 +168,6 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) struct task_struct *tsk = current; struct hrtimer *timer; ktime_t expires; - cputime_t cval, cinterval, nval, ninterval; /* * Validate the timevals in value. @@ -174,48 +202,10 @@ again: spin_unlock_irq(&tsk->sighand->siglock); break; case ITIMER_VIRTUAL: - nval = timeval_to_cputime(&value->it_value); - ninterval = timeval_to_cputime(&value->it_interval); - spin_lock_irq(&tsk->sighand->siglock); - cval = tsk->signal->it_virt_expires; - cinterval = tsk->signal->it_virt_incr; - if (!cputime_eq(cval, cputime_zero) || - !cputime_eq(nval, cputime_zero)) { - if (cputime_gt(nval, cputime_zero)) - nval = cputime_add(nval, - jiffies_to_cputime(1)); - set_process_cpu_timer(tsk, CPUCLOCK_VIRT, - &nval, &cval); - } - tsk->signal->it_virt_expires = nval; - tsk->signal->it_virt_incr = ninterval; - spin_unlock_irq(&tsk->sighand->siglock); - if (ovalue) { - cputime_to_timeval(cval, &ovalue->it_value); - cputime_to_timeval(cinterval, &ovalue->it_interval); - } + set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue); break; case ITIMER_PROF: - nval = timeval_to_cputime(&value->it_value); - ninterval = timeval_to_cputime(&value->it_interval); - spin_lock_irq(&tsk->sighand->siglock); - cval = tsk->signal->it_prof_expires; - cinterval = tsk->signal->it_prof_incr; - if (!cputime_eq(cval, cputime_zero) || - !cputime_eq(nval, cputime_zero)) { - if (cputime_gt(nval, cputime_zero)) - nval = cputime_add(nval, - jiffies_to_cputime(1)); - set_process_cpu_timer(tsk, CPUCLOCK_PROF, - &nval, &cval); - } - tsk->signal->it_prof_expires = nval; - tsk->signal->it_prof_incr = ninterval; - spin_unlock_irq(&tsk->sighand->siglock); - if (ovalue) { - cputime_to_timeval(cval, &ovalue->it_value); - cputime_to_timeval(cinterval, &ovalue->it_interval); - } + set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue); break; default: return -EINVAL; diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index bece7c0b67b..9b2d5e4dc8c 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -14,11 +14,11 @@ */ void update_rlimit_cpu(unsigned long rlim_new) { - cputime_t cputime; + cputime_t cputime = secs_to_cputime(rlim_new); + struct signal_struct *const sig = current->signal; - cputime = secs_to_cputime(rlim_new); - if (cputime_eq(current->signal->it_prof_expires, cputime_zero) || - cputime_gt(current->signal->it_prof_expires, cputime)) { + if (cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) || + cputime_gt(sig->it[CPUCLOCK_PROF].expires, cputime)) { spin_lock_irq(¤t->sighand->siglock); set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL); spin_unlock_irq(¤t->sighand->siglock); @@ -613,6 +613,9 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now) break; } } else { + struct signal_struct *const sig = p->signal; + union cpu_time_count *exp = &timer->it.cpu.expires; + /* * For a process timer, set the cached expiration time. */ @@ -620,30 +623,27 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now) default: BUG(); case CPUCLOCK_VIRT: - if (!cputime_eq(p->signal->it_virt_expires, + if (!cputime_eq(sig->it[CPUCLOCK_VIRT].expires, cputime_zero) && - cputime_lt(p->signal->it_virt_expires, - timer->it.cpu.expires.cpu)) + cputime_lt(sig->it[CPUCLOCK_VIRT].expires, + exp->cpu)) break; - p->signal->cputime_expires.virt_exp = - timer->it.cpu.expires.cpu; + sig->cputime_expires.virt_exp = exp->cpu; break; case CPUCLOCK_PROF: - if (!cputime_eq(p->signal->it_prof_expires, + if (!cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) && - cputime_lt(p->signal->it_prof_expires, - timer->it.cpu.expires.cpu)) + cputime_lt(sig->it[CPUCLOCK_PROF].expires, + exp->cpu)) break; - i = p->signal->rlim[RLIMIT_CPU].rlim_cur; + i = sig->rlim[RLIMIT_CPU].rlim_cur; if (i != RLIM_INFINITY && - i <= cputime_to_secs(timer->it.cpu.expires.cpu)) + i <= cputime_to_secs(exp->cpu)) break; - p->signal->cputime_expires.prof_exp = - timer->it.cpu.expires.cpu; + sig->cputime_expires.prof_exp = exp->cpu; break; case CPUCLOCK_SCHED: - p->signal->cputime_expires.sched_exp = - timer->it.cpu.expires.sched; + sig->cputime_expires.sched_exp = exp->sched; break; } } @@ -1070,6 +1070,27 @@ static void stop_process_timers(struct task_struct *tsk) spin_unlock_irqrestore(&cputimer->lock, flags); } +static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it, + cputime_t *expires, cputime_t cur_time, int signo) +{ + if (cputime_eq(it->expires, cputime_zero)) + return; + + if (cputime_ge(cur_time, it->expires)) { + it->expires = it->incr; + if (!cputime_eq(it->expires, cputime_zero)) + it->expires = cputime_add(it->expires, cur_time); + + __group_send_sig_info(signo, SEND_SIG_PRIV, tsk); + } + + if (!cputime_eq(it->expires, cputime_zero) && + (cputime_eq(*expires, cputime_zero) || + cputime_lt(it->expires, *expires))) { + *expires = it->expires; + } +} + /* * Check for any per-thread CPU timers that have fired and move them * off the tsk->*_timers list onto the firing list. Per-thread timers @@ -1089,10 +1110,10 @@ static void check_process_timers(struct task_struct *tsk, * Don't sample the current process CPU clocks if there are no timers. */ if (list_empty(&timers[CPUCLOCK_PROF]) && - cputime_eq(sig->it_prof_expires, cputime_zero) && + cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) && sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY && list_empty(&timers[CPUCLOCK_VIRT]) && - cputime_eq(sig->it_virt_expires, cputime_zero) && + cputime_eq(sig->it[CPUCLOCK_VIRT].expires, cputime_zero) && list_empty(&timers[CPUCLOCK_SCHED])) { stop_process_timers(tsk); return; @@ -1152,38 +1173,11 @@ static void check_process_timers(struct task_struct *tsk, /* * Check for the special case process timers. */ - if (!cputime_eq(sig->it_prof_expires, cputime_zero)) { - if (cputime_ge(ptime, sig->it_prof_expires)) { - /* ITIMER_PROF fires and reloads. */ - sig->it_prof_expires = sig->it_prof_incr; - if (!cputime_eq(sig->it_prof_expires, cputime_zero)) { - sig->it_prof_expires = cputime_add( - sig->it_prof_expires, ptime); - } - __group_send_sig_info(SIGPROF, SEND_SIG_PRIV, tsk); - } - if (!cputime_eq(sig->it_prof_expires, cputime_zero) && - (cputime_eq(prof_expires, cputime_zero) || - cputime_lt(sig->it_prof_expires, prof_expires))) { - prof_expires = sig->it_prof_expires; - } - } - if (!cputime_eq(sig->it_virt_expires, cputime_zero)) { - if (cputime_ge(utime, sig->it_virt_expires)) { - /* ITIMER_VIRTUAL fires and reloads. */ - sig->it_virt_expires = sig->it_virt_incr; - if (!cputime_eq(sig->it_virt_expires, cputime_zero)) { - sig->it_virt_expires = cputime_add( - sig->it_virt_expires, utime); - } - __group_send_sig_info(SIGVTALRM, SEND_SIG_PRIV, tsk); - } - if (!cputime_eq(sig->it_virt_expires, cputime_zero) && - (cputime_eq(virt_expires, cputime_zero) || - cputime_lt(sig->it_virt_expires, virt_expires))) { - virt_expires = sig->it_virt_expires; - } - } + check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime, + SIGPROF); + check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime, + SIGVTALRM); + if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { unsigned long psecs = cputime_to_secs(ptime); cputime_t x; -- cgit v1.2.3-70-g09d2 From 8356b5f9c424e5831715abbce747197c30d1fd71 Mon Sep 17 00:00:00 2001 From: Stanislaw Gruszka Date: Wed, 29 Jul 2009 12:15:27 +0200 Subject: itimers: Fix periodic tics precision Measure ITIMER_PROF and ITIMER_VIRT timers interval error between real ticks and requested by user. Take it into account when scheduling next tick. This patch introduce possibility where time between two consecutive tics is smaller then requested interval, it preserve however dependency that n tick is generated not earlier than n*interval time - counting from the beginning of periodic signal generation. Signed-off-by: Stanislaw Gruszka Acked-by: Peter Zijlstra Acked-by: Thomas Gleixner Cc: Oleg Nesterov Cc: Andrew Morton Cc: Paul Mackerras Cc: Benjamin Herrenschmidt LKML-Reference: <1248862529-6063-3-git-send-email-sgruszka@redhat.com> Signed-off-by: Ingo Molnar --- include/linux/sched.h | 2 ++ kernel/itimer.c | 24 +++++++++++++++++++++--- kernel/posix-cpu-timers.c | 20 +++++++++++++++++--- 3 files changed, 40 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/include/linux/sched.h b/include/linux/sched.h index 3b3efaddd95..a069e65e8bb 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -473,6 +473,8 @@ struct pacct_struct { struct cpu_itimer { cputime_t expires; cputime_t incr; + u32 error; + u32 incr_error; }; /** diff --git a/kernel/itimer.c b/kernel/itimer.c index 852c88ddd1f..21adff7b2a1 100644 --- a/kernel/itimer.c +++ b/kernel/itimer.c @@ -42,7 +42,7 @@ static struct timeval itimer_get_remtime(struct hrtimer *timer) } static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, - struct itimerval *value) + struct itimerval *const value) { cputime_t cval, cinterval; struct cpu_itimer *it = &tsk->signal->it[clock_id]; @@ -127,14 +127,32 @@ enum hrtimer_restart it_real_fn(struct hrtimer *timer) return HRTIMER_NORESTART; } +static inline u32 cputime_sub_ns(cputime_t ct, s64 real_ns) +{ + struct timespec ts; + s64 cpu_ns; + + cputime_to_timespec(ct, &ts); + cpu_ns = timespec_to_ns(&ts); + + return (cpu_ns <= real_ns) ? 0 : cpu_ns - real_ns; +} + static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, - struct itimerval *value, struct itimerval *ovalue) + const struct itimerval *const value, + struct itimerval *const ovalue) { - cputime_t cval, cinterval, nval, ninterval; + cputime_t cval, nval, cinterval, ninterval; + s64 ns_ninterval, ns_nval; struct cpu_itimer *it = &tsk->signal->it[clock_id]; nval = timeval_to_cputime(&value->it_value); + ns_nval = timeval_to_ns(&value->it_value); ninterval = timeval_to_cputime(&value->it_interval); + ns_ninterval = timeval_to_ns(&value->it_interval); + + it->incr_error = cputime_sub_ns(ninterval, ns_ninterval); + it->error = cputime_sub_ns(nval, ns_nval); spin_lock_irq(&tsk->sighand->siglock); diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index 9b2d5e4dc8c..b60d644ea4b 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -1070,6 +1070,8 @@ static void stop_process_timers(struct task_struct *tsk) spin_unlock_irqrestore(&cputimer->lock, flags); } +static u32 onecputick; + static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it, cputime_t *expires, cputime_t cur_time, int signo) { @@ -1077,9 +1079,16 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it, return; if (cputime_ge(cur_time, it->expires)) { - it->expires = it->incr; - if (!cputime_eq(it->expires, cputime_zero)) - it->expires = cputime_add(it->expires, cur_time); + if (!cputime_eq(it->incr, cputime_zero)) { + it->expires = cputime_add(it->expires, it->incr); + it->error += it->incr_error; + if (it->error >= onecputick) { + it->expires = cputime_sub(it->expires, + jiffies_to_cputime(1)); + it->error -= onecputick; + } + } else + it->expires = cputime_zero; __group_send_sig_info(signo, SEND_SIG_PRIV, tsk); } @@ -1696,10 +1705,15 @@ static __init int init_posix_cpu_timers(void) .nsleep = thread_cpu_nsleep, .nsleep_restart = thread_cpu_nsleep_restart, }; + struct timespec ts; register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process); register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread); + cputime_to_timespec(jiffies_to_cputime(1), &ts); + onecputick = ts.tv_nsec; + WARN_ON(ts.tv_sec != 0); + return 0; } __initcall(init_posix_cpu_timers); -- cgit v1.2.3-70-g09d2 From d1e3b6d195770bd422e3229b88edfc154b6a27dd Mon Sep 17 00:00:00 2001 From: Stanislaw Gruszka Date: Wed, 29 Jul 2009 12:15:28 +0200 Subject: itimers: Simplify arm_timer() code a bit Don't update values in expiration cache when new ones are equal. Add expire_le() and expire_gt() helpers to simplify the code. Signed-off-by: Stanislaw Gruszka Acked-by: Peter Zijlstra Acked-by: Thomas Gleixner Cc: Oleg Nesterov Cc: Andrew Morton Cc: Paul Mackerras Cc: Benjamin Herrenschmidt LKML-Reference: <1248862529-6063-4-git-send-email-sgruszka@redhat.com> Signed-off-by: Ingo Molnar --- kernel/posix-cpu-timers.c | 44 +++++++++++++++++++++++--------------------- 1 file changed, 23 insertions(+), 21 deletions(-) (limited to 'kernel') diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index b60d644ea4b..69c92374355 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -541,6 +541,17 @@ static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now) now); } +static inline int expires_gt(cputime_t expires, cputime_t new_exp) +{ + return cputime_eq(expires, cputime_zero) || + cputime_gt(expires, new_exp); +} + +static inline int expires_le(cputime_t expires, cputime_t new_exp) +{ + return !cputime_eq(expires, cputime_zero) && + cputime_le(expires, new_exp); +} /* * Insert the timer on the appropriate list before any timers that * expire later. This must be called with the tasklist_lock held @@ -585,31 +596,26 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now) */ if (CPUCLOCK_PERTHREAD(timer->it_clock)) { + union cpu_time_count *exp = &nt->expires; + switch (CPUCLOCK_WHICH(timer->it_clock)) { default: BUG(); case CPUCLOCK_PROF: - if (cputime_eq(p->cputime_expires.prof_exp, - cputime_zero) || - cputime_gt(p->cputime_expires.prof_exp, - nt->expires.cpu)) - p->cputime_expires.prof_exp = - nt->expires.cpu; + if (expires_gt(p->cputime_expires.prof_exp, + exp->cpu)) + p->cputime_expires.prof_exp = exp->cpu; break; case CPUCLOCK_VIRT: - if (cputime_eq(p->cputime_expires.virt_exp, - cputime_zero) || - cputime_gt(p->cputime_expires.virt_exp, - nt->expires.cpu)) - p->cputime_expires.virt_exp = - nt->expires.cpu; + if (expires_gt(p->cputime_expires.virt_exp, + exp->cpu)) + p->cputime_expires.virt_exp = exp->cpu; break; case CPUCLOCK_SCHED: if (p->cputime_expires.sched_exp == 0 || - p->cputime_expires.sched_exp > - nt->expires.sched) + p->cputime_expires.sched_exp > exp->sched) p->cputime_expires.sched_exp = - nt->expires.sched; + exp->sched; break; } } else { @@ -623,17 +629,13 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now) default: BUG(); case CPUCLOCK_VIRT: - if (!cputime_eq(sig->it[CPUCLOCK_VIRT].expires, - cputime_zero) && - cputime_lt(sig->it[CPUCLOCK_VIRT].expires, + if (expires_le(sig->it[CPUCLOCK_VIRT].expires, exp->cpu)) break; sig->cputime_expires.virt_exp = exp->cpu; break; case CPUCLOCK_PROF: - if (!cputime_eq(sig->it[CPUCLOCK_PROF].expires, - cputime_zero) && - cputime_lt(sig->it[CPUCLOCK_PROF].expires, + if (expires_le(sig->it[CPUCLOCK_PROF].expires, exp->cpu)) break; i = sig->rlim[RLIMIT_CPU].rlim_cur; -- cgit v1.2.3-70-g09d2 From a42548a18866e87092db93b771e6c5b060d78401 Mon Sep 17 00:00:00 2001 From: Stanislaw Gruszka Date: Wed, 29 Jul 2009 12:15:29 +0200 Subject: cputime: Optimize jiffies_to_cputime(1) For powerpc with CONFIG_VIRT_CPU_ACCOUNTING jiffies_to_cputime(1) is not compile time constant and run time calculations are quite expensive. To optimize we use precomputed value. For all other architectures is is preprocessor definition. Signed-off-by: Stanislaw Gruszka Acked-by: Peter Zijlstra Acked-by: Thomas Gleixner Cc: Oleg Nesterov Cc: Andrew Morton Cc: Paul Mackerras Cc: Benjamin Herrenschmidt LKML-Reference: <1248862529-6063-5-git-send-email-sgruszka@redhat.com> Signed-off-by: Ingo Molnar --- arch/ia64/include/asm/cputime.h | 1 + arch/powerpc/include/asm/cputime.h | 13 +++++++++++++ arch/powerpc/kernel/time.c | 4 ++++ arch/s390/include/asm/cputime.h | 1 + include/asm-generic/cputime.h | 1 + kernel/itimer.c | 4 ++-- kernel/posix-cpu-timers.c | 6 +++--- kernel/sched.c | 9 ++++----- 8 files changed, 29 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/arch/ia64/include/asm/cputime.h b/arch/ia64/include/asm/cputime.h index d20b998cb91..7fa8a859466 100644 --- a/arch/ia64/include/asm/cputime.h +++ b/arch/ia64/include/asm/cputime.h @@ -30,6 +30,7 @@ typedef u64 cputime_t; typedef u64 cputime64_t; #define cputime_zero ((cputime_t)0) +#define cputime_one_jiffy jiffies_to_cputime(1) #define cputime_max ((~((cputime_t)0) >> 1) - 1) #define cputime_add(__a, __b) ((__a) + (__b)) #define cputime_sub(__a, __b) ((__a) - (__b)) diff --git a/arch/powerpc/include/asm/cputime.h b/arch/powerpc/include/asm/cputime.h index f42e623030e..fa19f3fe05f 100644 --- a/arch/powerpc/include/asm/cputime.h +++ b/arch/powerpc/include/asm/cputime.h @@ -18,6 +18,9 @@ #ifndef CONFIG_VIRT_CPU_ACCOUNTING #include +#ifdef __KERNEL__ +static inline void setup_cputime_one_jiffy(void) { } +#endif #else #include @@ -48,6 +51,11 @@ typedef u64 cputime64_t; #ifdef __KERNEL__ +/* + * One jiffy in timebase units computed during initialization + */ +extern cputime_t cputime_one_jiffy; + /* * Convert cputime <-> jiffies */ @@ -89,6 +97,11 @@ static inline cputime_t jiffies_to_cputime(const unsigned long jif) return ct; } +static inline void setup_cputime_one_jiffy(void) +{ + cputime_one_jiffy = jiffies_to_cputime(1); +} + static inline cputime64_t jiffies64_to_cputime64(const u64 jif) { cputime_t ct; diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index eae4511ceea..211d7b0cd37 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -193,6 +193,8 @@ EXPORT_SYMBOL(__cputime_clockt_factor); DEFINE_PER_CPU(unsigned long, cputime_last_delta); DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); +cputime_t cputime_one_jiffy; + static void calc_cputime_factors(void) { struct div_result res; @@ -500,6 +502,7 @@ static int __init iSeries_tb_recal(void) tb_to_xs = divres.result_low; vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; vdso_data->tb_to_xs = tb_to_xs; + setup_cputime_one_jiffy(); } else { printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" @@ -945,6 +948,7 @@ void __init time_init(void) tb_ticks_per_usec = ppc_tb_freq / 1000000; tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000); calc_cputime_factors(); + setup_cputime_one_jiffy(); /* * Calculate the length of each tick in ns. It will not be diff --git a/arch/s390/include/asm/cputime.h b/arch/s390/include/asm/cputime.h index 7a3817a656d..24b1244aadb 100644 --- a/arch/s390/include/asm/cputime.h +++ b/arch/s390/include/asm/cputime.h @@ -42,6 +42,7 @@ __div(unsigned long long n, unsigned int base) #endif /* __s390x__ */ #define cputime_zero (0ULL) +#define cputime_one_jiffy jiffies_to_cputime(1) #define cputime_max ((~0UL >> 1) - 1) #define cputime_add(__a, __b) ((__a) + (__b)) #define cputime_sub(__a, __b) ((__a) - (__b)) diff --git a/include/asm-generic/cputime.h b/include/asm-generic/cputime.h index 1c1fa422d18..ca0f239f0e1 100644 --- a/include/asm-generic/cputime.h +++ b/include/asm-generic/cputime.h @@ -7,6 +7,7 @@ typedef unsigned long cputime_t; #define cputime_zero (0UL) +#define cputime_one_jiffy jiffies_to_cputime(1) #define cputime_max ((~0UL >> 1) - 1) #define cputime_add(__a, __b) ((__a) + (__b)) #define cputime_sub(__a, __b) ((__a) - (__b)) diff --git a/kernel/itimer.c b/kernel/itimer.c index 21adff7b2a1..8078a32d3b1 100644 --- a/kernel/itimer.c +++ b/kernel/itimer.c @@ -64,7 +64,7 @@ static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, if (cputime_le(cval, t)) /* about to fire */ - cval = jiffies_to_cputime(1); + cval = cputime_one_jiffy; else cval = cputime_sub(cval, t); } @@ -161,7 +161,7 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, if (!cputime_eq(cval, cputime_zero) || !cputime_eq(nval, cputime_zero)) { if (cputime_gt(nval, cputime_zero)) - nval = cputime_add(nval, jiffies_to_cputime(1)); + nval = cputime_add(nval, cputime_one_jiffy); set_process_cpu_timer(tsk, clock_id, &nval, &cval); } it->expires = nval; diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index 69c92374355..18bdde6f676 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -1086,7 +1086,7 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it, it->error += it->incr_error; if (it->error >= onecputick) { it->expires = cputime_sub(it->expires, - jiffies_to_cputime(1)); + cputime_one_jiffy); it->error -= onecputick; } } else @@ -1461,7 +1461,7 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx, if (!cputime_eq(*oldval, cputime_zero)) { if (cputime_le(*oldval, now.cpu)) { /* Just about to fire. */ - *oldval = jiffies_to_cputime(1); + *oldval = cputime_one_jiffy; } else { *oldval = cputime_sub(*oldval, now.cpu); } @@ -1712,7 +1712,7 @@ static __init int init_posix_cpu_timers(void) register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process); register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread); - cputime_to_timespec(jiffies_to_cputime(1), &ts); + cputime_to_timespec(cputime_one_jiffy, &ts); onecputick = ts.tv_nsec; WARN_ON(ts.tv_sec != 0); diff --git a/kernel/sched.c b/kernel/sched.c index 1b59e265273..8f977d5cc51 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5031,17 +5031,16 @@ void account_idle_time(cputime_t cputime) */ void account_process_tick(struct task_struct *p, int user_tick) { - cputime_t one_jiffy = jiffies_to_cputime(1); - cputime_t one_jiffy_scaled = cputime_to_scaled(one_jiffy); + cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); struct rq *rq = this_rq(); if (user_tick) - account_user_time(p, one_jiffy, one_jiffy_scaled); + account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET)) - account_system_time(p, HARDIRQ_OFFSET, one_jiffy, + account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy, one_jiffy_scaled); else - account_idle_time(one_jiffy); + account_idle_time(cputime_one_jiffy); } /* -- cgit v1.2.3-70-g09d2