diff options
| -rw-r--r-- | block/blk-iocost.c | 72 | ||||
| -rw-r--r-- | include/trace/events/iocost.h | 7 |
2 files changed, 47 insertions, 32 deletions
diff --git a/block/blk-iocost.c b/block/blk-iocost.c index f30f9b37fcf0..2496674bbbf4 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -476,14 +476,10 @@ struct ioc_gq { * `vtime_done` is the same but progressed on completion rather * than issue. The delta behind `vtime` represents the cost of * currently in-flight IOs. - * - * `last_vtime` is used to remember `vtime` at the end of the last - * period to calculate utilization. */ atomic64_t vtime; atomic64_t done_vtime; u64 abs_vdebt; - u64 last_vtime; /* * The period this iocg was last active in. Used for deactivation @@ -506,6 +502,9 @@ struct ioc_gq { struct hrtimer waitq_timer; struct hrtimer delay_timer; + /* timestamp at the latest activation */ + u64 activated_at; + /* statistics */ struct iocg_pcpu_stat __percpu *pcpu_stat; struct iocg_stat local_stat; @@ -514,6 +513,7 @@ struct ioc_gq { u64 last_stat_abs_vusage; /* usage is recorded as fractions of WEIGHT_ONE */ + u32 usage_delta_us; int usage_idx; u32 usages[NR_USAGE_SLOTS]; @@ -1159,7 +1159,7 @@ static bool iocg_activate(struct ioc_gq *iocg, struct ioc_now *now) TRACE_IOCG_PATH(iocg_activate, iocg, now, last_period, cur_period, vtime); - iocg->last_vtime = vtime; + iocg->activated_at = now->now; if (ioc->running == IOC_IDLE) { ioc->running = IOC_RUNNING; @@ -1451,7 +1451,8 @@ static void iocg_flush_stat_one(struct ioc_gq *iocg, struct ioc_now *now) vusage_delta = abs_vusage - iocg->last_stat_abs_vusage; iocg->last_stat_abs_vusage = abs_vusage; - iocg->local_stat.usage_us += div64_u64(vusage_delta, now->vrate); + iocg->usage_delta_us = div64_u64(vusage_delta, now->vrate); + iocg->local_stat.usage_us += iocg->usage_delta_us; new_stat.usage_us = iocg->local_stat.usage_us + iocg->desc_stat.usage_us; @@ -1558,8 +1559,9 @@ static void ioc_timer_fn(struct timer_list *timer) /* calc usages and see whether some weights need to be moved around */ list_for_each_entry(iocg, &ioc->active_iocgs, active_list) { - u64 vdone, vtime, vusage, vmin; + u64 vdone, vtime, usage_us, vmin; u32 hw_active, hw_inuse, usage; + int uidx; /* * Collect unused and wind vtime closer to vnow to prevent @@ -1583,27 +1585,44 @@ static void ioc_timer_fn(struct timer_list *timer) time_before64(vdone, now.vnow - period_vtime)) nr_lagging++; - if (waitqueue_active(&iocg->waitq)) - vusage = now.vnow - iocg->last_vtime; - else if (time_before64(iocg->last_vtime, vtime)) - vusage = vtime - iocg->last_vtime; - else - vusage = 0; - - iocg->last_vtime += vusage; /* - * Factor in in-flight vtime into vusage to avoid - * high-latency completions appearing as idle. This should - * be done after the above ->last_time adjustment. + * Determine absolute usage factoring in pending and in-flight + * IOs to avoid stalls and high-latency completions appearing as + * idle. */ - vusage = max(vusage, vtime - vdone); - - /* calculate hweight based usage ratio and record */ - if (vusage) { - usage = DIV64_U64_ROUND_UP(vusage * hw_inuse, - period_vtime); - iocg->usage_idx = (iocg->usage_idx + 1) % NR_USAGE_SLOTS; - iocg->usages[iocg->usage_idx] = usage; + usage_us = iocg->usage_delta_us; + if (waitqueue_active(&iocg->waitq) && time_before64(vtime, now.vnow)) + usage_us += DIV64_U64_ROUND_UP( + cost_to_abs_cost(now.vnow - vtime, hw_inuse), + now.vrate); + if (vdone != vtime) { + u64 inflight_us = DIV64_U64_ROUND_UP( + cost_to_abs_cost(vtime - vdone, hw_inuse), + now.vrate); + usage_us = max(usage_us, inflight_us); + } + + /* convert to hweight based usage ratio and record */ + uidx = (iocg->usage_idx + 1) % NR_USAGE_SLOTS; + + if (time_after64(vtime, now.vnow - ioc->margins.min)) { + iocg->usage_idx = uidx; + iocg->usages[uidx] = WEIGHT_ONE; + } else if (usage_us) { + u64 started_at, dur; + + if (time_after64(iocg->activated_at, ioc->period_at)) + started_at = iocg->activated_at; + else + started_at = ioc->period_at; + + dur = max_t(u64, now.now - started_at, 1); + usage = clamp_t(u32, + DIV64_U64_ROUND_UP(usage_us * WEIGHT_ONE, dur), + 1, WEIGHT_ONE); + + iocg->usage_idx = uidx; + iocg->usages[uidx] = usage; } else { usage = 0; } @@ -1620,7 +1639,6 @@ static void ioc_timer_fn(struct timer_list *timer) /* throw away surplus vtime */ atomic64_add(delta, &iocg->vtime); atomic64_add(delta, &iocg->done_vtime); - iocg->last_vtime += delta; /* if usage is sufficiently low, maybe it can donate */ if (surplus_adjusted_hweight_inuse(usage, hw_inuse)) { iocg->has_surplus = true; diff --git a/include/trace/events/iocost.h b/include/trace/events/iocost.h index c2f580fd371b..a905ecc0342f 100644 --- a/include/trace/events/iocost.h +++ b/include/trace/events/iocost.h @@ -26,7 +26,6 @@ TRACE_EVENT(iocost_iocg_activate, __field(u64, vrate) __field(u64, last_period) __field(u64, cur_period) - __field(u64, last_vtime) __field(u64, vtime) __field(u32, weight) __field(u32, inuse) @@ -42,7 +41,6 @@ TRACE_EVENT(iocost_iocg_activate, __entry->vrate = now->vrate; __entry->last_period = last_period; __entry->cur_period = cur_period; - __entry->last_vtime = iocg->last_vtime; __entry->vtime = vtime; __entry->weight = iocg->weight; __entry->inuse = iocg->inuse; @@ -51,13 +49,12 @@ TRACE_EVENT(iocost_iocg_activate, ), TP_printk("[%s:%s] now=%llu:%llu vrate=%llu " - "period=%llu->%llu vtime=%llu->%llu " + "period=%llu->%llu vtime=%llu " "weight=%u/%u hweight=%llu/%llu", __get_str(devname), __get_str(cgroup), __entry->now, __entry->vnow, __entry->vrate, __entry->last_period, __entry->cur_period, - __entry->last_vtime, __entry->vtime, - __entry->inuse, __entry->weight, + __entry->vtime, __entry->inuse, __entry->weight, __entry->hweight_inuse, __entry->hweight_active ) ); |