diff options
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event.c | 185 | ||||
| -rw-r--r-- | include/linux/bitops.h | 10 |
2 files changed, 140 insertions, 55 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 2bda212a001..5a469d3d0c6 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -484,18 +484,145 @@ static inline int is_x86_event(struct perf_event *event) return event->pmu == &pmu; } +/* + * Event scheduler state: + * + * Assign events iterating over all events and counters, beginning + * with events with least weights first. Keep the current iterator + * state in struct sched_state. + */ +struct sched_state { + int weight; + int event; /* event index */ + int counter; /* counter index */ + int unassigned; /* number of events to be assigned left */ + unsigned long used[BITS_TO_LONGS(X86_PMC_IDX_MAX)]; +}; + +struct perf_sched { + int max_weight; + int max_events; + struct event_constraint **constraints; + struct sched_state state; +}; + +/* + * Initialize interator that runs through all events and counters. + */ +static void perf_sched_init(struct perf_sched *sched, struct event_constraint **c, + int num, int wmin, int wmax) +{ + int idx; + + memset(sched, 0, sizeof(*sched)); + sched->max_events = num; + sched->max_weight = wmax; + sched->constraints = c; + + for (idx = 0; idx < num; idx++) { + if (c[idx]->weight == wmin) + break; + } + + sched->state.event = idx; /* start with min weight */ + sched->state.weight = wmin; + sched->state.unassigned = num; +} + +/* + * Select a counter for the current event to schedule. Return true on + * success. + */ +static bool perf_sched_find_counter(struct perf_sched *sched) +{ + struct event_constraint *c; + int idx; + + if (!sched->state.unassigned) + return false; + + if (sched->state.event >= sched->max_events) + return false; + + c = sched->constraints[sched->state.event]; + + /* Grab the first unused counter starting with idx */ + idx = sched->state.counter; + for_each_set_bit_cont(idx, c->idxmsk, X86_PMC_IDX_MAX) { + if (!__test_and_set_bit(idx, sched->state.used)) + break; + } + sched->state.counter = idx; + + if (idx >= X86_PMC_IDX_MAX) + return false; + + return true; +} + +/* + * Go through all unassigned events and find the next one to schedule. + * Take events with the least weight first. Return true on success. + */ +static bool perf_sched_next_event(struct perf_sched *sched) +{ + struct event_constraint *c; + + if (!sched->state.unassigned || !--sched->state.unassigned) + return false; + + do { + /* next event */ + sched->state.event++; + if (sched->state.event >= sched->max_events) { + /* next weight */ + sched->state.event = 0; + sched->state.weight++; + if (sched->state.weight > sched->max_weight) + return false; + } + c = sched->constraints[sched->state.event]; + } while (c->weight != sched->state.weight); + + sched->state.counter = 0; /* start with first counter */ + + return true; +} + +/* + * Assign a counter for each event. + */ +static int perf_assign_events(struct event_constraint **constraints, int n, + int wmin, int wmax, int *assign) +{ + struct perf_sched sched; + + perf_sched_init(&sched, constraints, n, wmin, wmax); + + do { + if (!perf_sched_find_counter(&sched)) + break; /* failed */ + if (assign) + assign[sched.state.event] = sched.state.counter; + } while (perf_sched_next_event(&sched)); + + return sched.state.unassigned; +} + int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign) { struct event_constraint *c, *constraints[X86_PMC_IDX_MAX]; unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)]; - int i, j, w, wmax, num = 0; + int i, wmin, wmax, num = 0; struct hw_perf_event *hwc; bitmap_zero(used_mask, X86_PMC_IDX_MAX); - for (i = 0; i < n; i++) { + for (i = 0, wmin = X86_PMC_IDX_MAX, wmax = 0; i < n; i++) { c = x86_pmu.get_event_constraints(cpuc, cpuc->event_list[i]); constraints[i] = c; + wmin = min(wmin, c->weight); + wmax = max(wmax, c->weight); } /* @@ -521,59 +648,11 @@ int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign) if (assign) assign[i] = hwc->idx; } - if (i == n) - goto done; - /* - * begin slow path - */ + /* slow path */ + if (i != n) + num = perf_assign_events(constraints, n, wmin, wmax, assign); - bitmap_zero(used_mask, X86_PMC_IDX_MAX); - - /* - * weight = number of possible counters - * - * 1 = most constrained, only works on one counter - * wmax = least constrained, works on any counter - * - * assign events to counters starting with most - * constrained events. - */ - wmax = x86_pmu.num_counters; - - /* - * when fixed event counters are present, - * wmax is incremented by 1 to account - * for one more choice - */ - if (x86_pmu.num_counters_fixed) - wmax++; - - for (w = 1, num = n; num && w <= wmax; w++) { - /* for each event */ - for (i = 0; num && i < n; i++) { - c = constraints[i]; - hwc = &cpuc->event_list[i]->hw; - - if (c->weight != w) - continue; - - for_each_set_bit(j, c->idxmsk, X86_PMC_IDX_MAX) { - if (!test_bit(j, used_mask)) - break; - } - - if (j == X86_PMC_IDX_MAX) - break; - - __set_bit(j, used_mask); - - if (assign) - assign[i] = j; - num--; - } - } -done: /* * scheduling failed or is just a simulation, * free resources if necessary diff --git a/include/linux/bitops.h b/include/linux/bitops.h index a3ef66a2a08..3c1063acb2a 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -22,8 +22,14 @@ extern unsigned long __sw_hweight64(__u64 w); #include <asm/bitops.h> #define for_each_set_bit(bit, addr, size) \ - for ((bit) = find_first_bit((addr), (size)); \ - (bit) < (size); \ + for ((bit) = find_first_bit((addr), (size)); \ + (bit) < (size); \ + (bit) = find_next_bit((addr), (size), (bit) + 1)) + +/* same as for_each_set_bit() but use bit as value to start with */ +#define for_each_set_bit_cont(bit, addr, size) \ + for ((bit) = find_next_bit((addr), (size), (bit)); \ + (bit) < (size); \ (bit) = find_next_bit((addr), (size), (bit) + 1)) static __inline__ int get_bitmask_order(unsigned int count) |