From: Tejun Heo <tj@kernel.org> To: axboe@kernel.dk Cc: linux-block@vger.kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, newella@fb.com, Tejun Heo <tj@kernel.org> Subject: [PATCH 26/27] blk-iocost: add three debug stat - cost.wait, indebt and indelay Date: Tue, 1 Sep 2020 14:52:56 -0400 [thread overview] Message-ID: <20200901185257.645114-27-tj@kernel.org> (raw) In-Reply-To: <20200901185257.645114-1-tj@kernel.org> These are really cheap to collect and can be useful in debugging iocost behavior. Add them as debug stats for now. Signed-off-by: Tejun Heo <tj@kernel.org> --- block/blk-iocost.c | 77 +++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 72 insertions(+), 5 deletions(-) diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 9366527d8c12..fc897bb142bc 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -452,6 +452,9 @@ struct iocg_pcpu_stat { struct iocg_stat { u64 usage_us; + u64 wait_us; + u64 indebt_us; + u64 indelay_us; }; /* per device-cgroup pair */ @@ -538,6 +541,9 @@ struct ioc_gq { struct iocg_stat last_stat; u64 last_stat_abs_vusage; u64 usage_delta_us; + u64 wait_since; + u64 indebt_since; + u64 indelay_since; /* this iocg's depth in the hierarchy and ancestors including self */ int level; @@ -1303,9 +1309,15 @@ static bool iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now) } if (delay >= MIN_DELAY) { + if (!iocg->indelay_since) + iocg->indelay_since = now->now; blkcg_set_delay(blkg, delay * NSEC_PER_USEC); return true; } else { + if (iocg->indelay_since) { + iocg->local_stat.indelay_us += now->now - iocg->indelay_since; + iocg->indelay_since = 0; + } iocg->delay = 0; blkcg_clear_delay(blkg); return false; @@ -1325,8 +1337,10 @@ static void iocg_incur_debt(struct ioc_gq *iocg, u64 abs_cost, * Once in debt, debt handling owns inuse. @iocg stays at the minimum * inuse donating all of it share to others until its debt is paid off. */ - if (!iocg->abs_vdebt && abs_cost) + if (!iocg->abs_vdebt && abs_cost) { + iocg->indebt_since = now->now; propagate_weights(iocg, iocg->active, 0, false, now); + } iocg->abs_vdebt += abs_cost; @@ -1348,9 +1362,13 @@ static void iocg_pay_debt(struct ioc_gq *iocg, u64 abs_vpay, iocg->abs_vdebt -= min(abs_vpay, iocg->abs_vdebt); /* if debt is paid in full, restore inuse */ - if (!iocg->abs_vdebt) + if (!iocg->abs_vdebt) { + iocg->local_stat.indebt_us += now->now - iocg->indebt_since; + iocg->indebt_since = 0; + propagate_weights(iocg, iocg->active, iocg->last_inuse, false, now); + } } static int iocg_wake_fn(struct wait_queue_entry *wq_entry, unsigned mode, @@ -1436,8 +1454,17 @@ static void iocg_kick_waitq(struct ioc_gq *iocg, bool pay_debt, __wake_up_locked_key(&iocg->waitq, TASK_NORMAL, &ctx); - if (!waitqueue_active(&iocg->waitq)) + if (!waitqueue_active(&iocg->waitq)) { + if (iocg->wait_since) { + iocg->local_stat.wait_us += now->now - iocg->wait_since; + iocg->wait_since = 0; + } return; + } + + if (!iocg->wait_since) + iocg->wait_since = now->now; + if (WARN_ON_ONCE(ctx.vbudget >= 0)) return; @@ -1579,8 +1606,15 @@ static void iocg_flush_stat_one(struct ioc_gq *iocg, struct ioc_now *now) iocg->usage_delta_us = div64_u64(vusage_delta, ioc->vtime_base_rate); iocg->local_stat.usage_us += iocg->usage_delta_us; + /* propagate upwards */ new_stat.usage_us = iocg->local_stat.usage_us + iocg->desc_stat.usage_us; + new_stat.wait_us = + iocg->local_stat.wait_us + iocg->desc_stat.wait_us; + new_stat.indebt_us = + iocg->local_stat.indebt_us + iocg->desc_stat.indebt_us; + new_stat.indelay_us = + iocg->local_stat.indelay_us + iocg->desc_stat.indelay_us; /* propagate the deltas to the parent */ if (iocg->level > 0) { @@ -1589,6 +1623,12 @@ static void iocg_flush_stat_one(struct ioc_gq *iocg, struct ioc_now *now) parent_stat->usage_us += new_stat.usage_us - iocg->last_stat.usage_us; + parent_stat->wait_us += + new_stat.wait_us - iocg->last_stat.wait_us; + parent_stat->indebt_us += + new_stat.indebt_us - iocg->last_stat.indebt_us; + parent_stat->indelay_us += + new_stat.indelay_us - iocg->last_stat.indelay_us; } iocg->last_stat = new_stat; @@ -1961,8 +2001,6 @@ static void ioc_timer_fn(struct timer_list *timer) return; } - iocg_flush_stat(&ioc->active_iocgs, &now); - /* * Waiters determine the sleep durations based on the vrate they * saw at the time of sleep. If vrate has increased, some waiters @@ -1976,6 +2014,22 @@ static void ioc_timer_fn(struct timer_list *timer) spin_lock(&iocg->waitq.lock); + /* flush wait and indebt stat deltas */ + if (iocg->wait_since) { + iocg->local_stat.wait_us += now.now - iocg->wait_since; + iocg->wait_since = now.now; + } + if (iocg->indebt_since) { + iocg->local_stat.indebt_us += + now.now - iocg->indebt_since; + iocg->indebt_since = now.now; + } + if (iocg->indelay_since) { + iocg->local_stat.indelay_us += + now.now - iocg->indelay_since; + iocg->indelay_since = now.now; + } + if (waitqueue_active(&iocg->waitq) || iocg->abs_vdebt || iocg->delay) { /* might be oversleeping vtime / hweight changes, kick */ @@ -2010,6 +2064,12 @@ static void ioc_timer_fn(struct timer_list *timer) } commit_weights(ioc); + /* + * Wait and indebt stat are flushed above and the donation calculation + * below needs updated usage stat. Let's bring stat up-to-date. + */ + iocg_flush_stat(&ioc->active_iocgs, &now); + /* calc usage and see whether some weights need to be moved around */ list_for_each_entry(iocg, &ioc->active_iocgs, active_list) { u64 vdone, vtime, usage_us, usage_dur; @@ -2835,6 +2895,13 @@ static size_t ioc_pd_stat(struct blkg_policy_data *pd, char *buf, size_t size) pos += scnprintf(buf + pos, size - pos, " cost.usage=%llu", iocg->last_stat.usage_us); + if (blkcg_debug_stats) + pos += scnprintf(buf + pos, size - pos, + " cost.wait=%llu cost.indebt=%llu cost.indelay=%llu", + iocg->last_stat.wait_us, + iocg->last_stat.indebt_us, + iocg->last_stat.indelay_us); + return pos; } -- 2.26.2
WARNING: multiple messages have this Message-ID (diff)
From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> To: axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org Cc: linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-team-b10kYP2dOMg@public.gmane.org, newella-b10kYP2dOMg@public.gmane.org, Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Subject: [PATCH 26/27] blk-iocost: add three debug stat - cost.wait, indebt and indelay Date: Tue, 1 Sep 2020 14:52:56 -0400 [thread overview] Message-ID: <20200901185257.645114-27-tj@kernel.org> (raw) In-Reply-To: <20200901185257.645114-1-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> These are really cheap to collect and can be useful in debugging iocost behavior. Add them as debug stats for now. Signed-off-by: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> --- block/blk-iocost.c | 77 +++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 72 insertions(+), 5 deletions(-) diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 9366527d8c12..fc897bb142bc 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -452,6 +452,9 @@ struct iocg_pcpu_stat { struct iocg_stat { u64 usage_us; + u64 wait_us; + u64 indebt_us; + u64 indelay_us; }; /* per device-cgroup pair */ @@ -538,6 +541,9 @@ struct ioc_gq { struct iocg_stat last_stat; u64 last_stat_abs_vusage; u64 usage_delta_us; + u64 wait_since; + u64 indebt_since; + u64 indelay_since; /* this iocg's depth in the hierarchy and ancestors including self */ int level; @@ -1303,9 +1309,15 @@ static bool iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now) } if (delay >= MIN_DELAY) { + if (!iocg->indelay_since) + iocg->indelay_since = now->now; blkcg_set_delay(blkg, delay * NSEC_PER_USEC); return true; } else { + if (iocg->indelay_since) { + iocg->local_stat.indelay_us += now->now - iocg->indelay_since; + iocg->indelay_since = 0; + } iocg->delay = 0; blkcg_clear_delay(blkg); return false; @@ -1325,8 +1337,10 @@ static void iocg_incur_debt(struct ioc_gq *iocg, u64 abs_cost, * Once in debt, debt handling owns inuse. @iocg stays at the minimum * inuse donating all of it share to others until its debt is paid off. */ - if (!iocg->abs_vdebt && abs_cost) + if (!iocg->abs_vdebt && abs_cost) { + iocg->indebt_since = now->now; propagate_weights(iocg, iocg->active, 0, false, now); + } iocg->abs_vdebt += abs_cost; @@ -1348,9 +1362,13 @@ static void iocg_pay_debt(struct ioc_gq *iocg, u64 abs_vpay, iocg->abs_vdebt -= min(abs_vpay, iocg->abs_vdebt); /* if debt is paid in full, restore inuse */ - if (!iocg->abs_vdebt) + if (!iocg->abs_vdebt) { + iocg->local_stat.indebt_us += now->now - iocg->indebt_since; + iocg->indebt_since = 0; + propagate_weights(iocg, iocg->active, iocg->last_inuse, false, now); + } } static int iocg_wake_fn(struct wait_queue_entry *wq_entry, unsigned mode, @@ -1436,8 +1454,17 @@ static void iocg_kick_waitq(struct ioc_gq *iocg, bool pay_debt, __wake_up_locked_key(&iocg->waitq, TASK_NORMAL, &ctx); - if (!waitqueue_active(&iocg->waitq)) + if (!waitqueue_active(&iocg->waitq)) { + if (iocg->wait_since) { + iocg->local_stat.wait_us += now->now - iocg->wait_since; + iocg->wait_since = 0; + } return; + } + + if (!iocg->wait_since) + iocg->wait_since = now->now; + if (WARN_ON_ONCE(ctx.vbudget >= 0)) return; @@ -1579,8 +1606,15 @@ static void iocg_flush_stat_one(struct ioc_gq *iocg, struct ioc_now *now) iocg->usage_delta_us = div64_u64(vusage_delta, ioc->vtime_base_rate); iocg->local_stat.usage_us += iocg->usage_delta_us; + /* propagate upwards */ new_stat.usage_us = iocg->local_stat.usage_us + iocg->desc_stat.usage_us; + new_stat.wait_us = + iocg->local_stat.wait_us + iocg->desc_stat.wait_us; + new_stat.indebt_us = + iocg->local_stat.indebt_us + iocg->desc_stat.indebt_us; + new_stat.indelay_us = + iocg->local_stat.indelay_us + iocg->desc_stat.indelay_us; /* propagate the deltas to the parent */ if (iocg->level > 0) { @@ -1589,6 +1623,12 @@ static void iocg_flush_stat_one(struct ioc_gq *iocg, struct ioc_now *now) parent_stat->usage_us += new_stat.usage_us - iocg->last_stat.usage_us; + parent_stat->wait_us += + new_stat.wait_us - iocg->last_stat.wait_us; + parent_stat->indebt_us += + new_stat.indebt_us - iocg->last_stat.indebt_us; + parent_stat->indelay_us += + new_stat.indelay_us - iocg->last_stat.indelay_us; } iocg->last_stat = new_stat; @@ -1961,8 +2001,6 @@ static void ioc_timer_fn(struct timer_list *timer) return; } - iocg_flush_stat(&ioc->active_iocgs, &now); - /* * Waiters determine the sleep durations based on the vrate they * saw at the time of sleep. If vrate has increased, some waiters @@ -1976,6 +2014,22 @@ static void ioc_timer_fn(struct timer_list *timer) spin_lock(&iocg->waitq.lock); + /* flush wait and indebt stat deltas */ + if (iocg->wait_since) { + iocg->local_stat.wait_us += now.now - iocg->wait_since; + iocg->wait_since = now.now; + } + if (iocg->indebt_since) { + iocg->local_stat.indebt_us += + now.now - iocg->indebt_since; + iocg->indebt_since = now.now; + } + if (iocg->indelay_since) { + iocg->local_stat.indelay_us += + now.now - iocg->indelay_since; + iocg->indelay_since = now.now; + } + if (waitqueue_active(&iocg->waitq) || iocg->abs_vdebt || iocg->delay) { /* might be oversleeping vtime / hweight changes, kick */ @@ -2010,6 +2064,12 @@ static void ioc_timer_fn(struct timer_list *timer) } commit_weights(ioc); + /* + * Wait and indebt stat are flushed above and the donation calculation + * below needs updated usage stat. Let's bring stat up-to-date. + */ + iocg_flush_stat(&ioc->active_iocgs, &now); + /* calc usage and see whether some weights need to be moved around */ list_for_each_entry(iocg, &ioc->active_iocgs, active_list) { u64 vdone, vtime, usage_us, usage_dur; @@ -2835,6 +2895,13 @@ static size_t ioc_pd_stat(struct blkg_policy_data *pd, char *buf, size_t size) pos += scnprintf(buf + pos, size - pos, " cost.usage=%llu", iocg->last_stat.usage_us); + if (blkcg_debug_stats) + pos += scnprintf(buf + pos, size - pos, + " cost.wait=%llu cost.indebt=%llu cost.indelay=%llu", + iocg->last_stat.wait_us, + iocg->last_stat.indebt_us, + iocg->last_stat.indelay_us); + return pos; } -- 2.26.2
next prev parent reply other threads:[~2020-09-01 18:54 UTC|newest] Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-09-01 18:52 [PATCHSET for-5.10/block] blk-iocost: iocost: improve donation, debt and excess handling Tejun Heo 2020-09-01 18:52 ` [PATCH 01/27] blk-iocost: ioc_pd_free() shouldn't assume irq disabled Tejun Heo 2020-09-01 18:52 ` [PATCH 02/27] blk-stat: make q->stats->lock irqsafe Tejun Heo 2020-09-01 18:52 ` Tejun Heo 2020-09-01 18:52 ` [PATCH 03/27] blk-iocost: use local[64]_t for percpu stat Tejun Heo 2020-09-01 18:52 ` Tejun Heo 2020-11-20 21:51 ` Stafford Horne 2020-11-20 22:13 ` Tejun Heo 2020-11-20 22:13 ` Tejun Heo 2020-09-01 18:52 ` [PATCH 04/27] blk-iocost: rename propagate_active_weights() to propagate_weights() Tejun Heo 2020-09-01 18:52 ` [PATCH 05/27] blk-iocost: clamp inuse and skip noops in __propagate_weights() Tejun Heo 2020-09-01 18:52 ` [PATCH 06/27] blk-iocost: move iocg_kick_delay() above iocg_kick_waitq() Tejun Heo 2020-09-01 18:52 ` [PATCH 07/27] blk-iocost: make iocg_kick_waitq() call iocg_kick_delay() after paying debt Tejun Heo 2020-09-01 18:52 ` [PATCH 08/27] blk-iocost: s/HWEIGHT_WHOLE/WEIGHT_ONE/g Tejun Heo 2020-09-01 18:52 ` Tejun Heo 2020-09-01 18:52 ` [PATCH 09/27] blk-iocost: use WEIGHT_ONE based fixed point number for weights Tejun Heo 2020-09-01 18:52 ` [PATCH 10/27] blk-iocost: make ioc_now->now and ioc->period_at 64bit Tejun Heo 2020-09-01 18:52 ` [PATCH 11/27] blk-iocost: streamline vtime margin and timer slack handling Tejun Heo 2020-09-01 18:52 ` [PATCH 12/27] blk-iocost: grab ioc->lock for debt handling Tejun Heo 2020-09-01 18:52 ` [PATCH 13/27] blk-iocost: add absolute usage stat Tejun Heo 2020-09-01 18:52 ` Tejun Heo 2020-09-01 18:52 ` [PATCH 14/27] blk-iocost: calculate iocg->usages[] from iocg->local_stat.usage_us Tejun Heo 2020-09-01 18:52 ` Tejun Heo 2020-09-01 18:52 ` [PATCH 15/27] blk-iocost: replace iocg->has_surplus with ->surplus_list Tejun Heo 2020-09-01 18:52 ` [PATCH 16/27] blk-iocost: decouple vrate adjustment from surplus transfers Tejun Heo 2020-09-01 18:52 ` Tejun Heo 2020-09-01 18:52 ` [PATCH 17/27] blk-iocost: restructure surplus donation logic Tejun Heo 2020-09-01 18:52 ` [PATCH 18/27] blk-iocost: implement Andy's method for donation weight updates Tejun Heo 2020-09-01 18:52 ` [PATCH 19/27] blk-iocost: revamp donation amount determination Tejun Heo 2020-09-01 18:52 ` [PATCH 20/27] blk-iocost: revamp in-period donation snapbacks Tejun Heo 2020-09-01 18:52 ` Tejun Heo 2020-09-01 18:52 ` [PATCH 21/27] blk-iocost: revamp debt handling Tejun Heo 2020-09-01 18:52 ` Tejun Heo 2020-09-01 18:52 ` [PATCH 22/27] blk-iocost: implement delay adjustment hysteresis Tejun Heo 2020-09-01 18:52 ` [PATCH 23/27] blk-iocost: halve debts if device stays idle Tejun Heo 2020-09-01 18:52 ` [PATCH 24/27] blk-iocost: implement vtime loss compensation Tejun Heo 2020-09-01 18:52 ` [PATCH 25/27] blk-iocost: restore inuse update tracepoints Tejun Heo 2020-09-01 18:52 ` Tejun Heo [this message] 2020-09-01 18:52 ` [PATCH 26/27] blk-iocost: add three debug stat - cost.wait, indebt and indelay Tejun Heo 2020-09-01 18:52 ` [PATCH 27/27] blk-iocost: update iocost_monitor.py Tejun Heo 2020-09-01 22:57 ` [PATCHSET for-5.10/block] blk-iocost: iocost: improve donation, debt and excess handling Jens Axboe 2020-09-01 22:57 ` Jens Axboe
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