From 3fcb9d17206e31630f802a3ab52081d1342b8ed9 Mon Sep 17 00:00:00 2001 From: Xiaobing Li Date: Wed, 28 Feb 2024 17:12:51 +0800 Subject: [PATCH] io_uring/sqpoll: statistics of the true utilization of sq threads Count the running time and actual IO processing time of the sqpoll thread, and output the statistical data to fdinfo. Variable description: "work_time" in the code represents the sum of the jiffies of the sq thread actually processing IO, that is, how many milliseconds it actually takes to process IO. "total_time" represents the total time that the sq thread has elapsed from the beginning of the loop to the current time point, that is, how many milliseconds it has spent in total. The test tool is fio, and its parameters are as follows: [global] ioengine=io_uring direct=1 group_reporting bs=128k norandommap=1 randrepeat=0 refill_buffers ramp_time=30s time_based runtime=1m clocksource=clock_gettime overwrite=1 log_avg_msec=1000 numjobs=1 [disk0] filename=/dev/nvme0n1 rw=read iodepth=16 hipri sqthread_poll=1 The test results are as follows: Every 2.0s: cat /proc/9230/fdinfo/6 | grep -E Sq SqMask: 0x3 SqHead: 3197153 SqTail: 3197153 CachedSqHead: 3197153 SqThread: 9231 SqThreadCpu: 11 SqTotalTime: 18099614 SqWorkTime: 16748316 The test results corresponding to different iodepths are as follows: |-----------|-------|-------|-------|------|-------| | iodepth | 1 | 4 | 8 | 16 | 64 | |-----------|-------|-------|-------|------|-------| |utilization| 2.9% | 8.8% | 10.9% | 92.9%| 84.4% | |-----------|-------|-------|-------|------|-------| | idle | 97.1% | 91.2% | 89.1% | 7.1% | 15.6% | |-----------|-------|-------|-------|------|-------| Signed-off-by: Xiaobing Li Link: https://lore.kernel.org/r/20240228091251.543383-1-xiaobing.li@samsung.com Signed-off-by: Jens Axboe --- io_uring/fdinfo.c | 7 +++++++ io_uring/sqpoll.c | 17 ++++++++++++++++- io_uring/sqpoll.h | 1 + 3 files changed, 24 insertions(+), 1 deletion(-) diff --git a/io_uring/fdinfo.c b/io_uring/fdinfo.c index 976e9500f651..37afc5bac279 100644 --- a/io_uring/fdinfo.c +++ b/io_uring/fdinfo.c @@ -55,6 +55,7 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f) struct io_ring_ctx *ctx = f->private_data; struct io_overflow_cqe *ocqe; struct io_rings *r = ctx->rings; + struct rusage sq_usage; unsigned int sq_mask = ctx->sq_entries - 1, cq_mask = ctx->cq_entries - 1; unsigned int sq_head = READ_ONCE(r->sq.head); unsigned int sq_tail = READ_ONCE(r->sq.tail); @@ -64,6 +65,7 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f) unsigned int sq_shift = 0; unsigned int sq_entries, cq_entries; int sq_pid = -1, sq_cpu = -1; + u64 sq_total_time = 0, sq_work_time = 0; bool has_lock; unsigned int i; @@ -147,10 +149,15 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f) sq_pid = sq->task_pid; sq_cpu = sq->sq_cpu; + getrusage(sq->thread, RUSAGE_SELF, &sq_usage); + sq_total_time = sq_usage.ru_stime.tv_sec * 1000000 + sq_usage.ru_stime.tv_usec; + sq_work_time = sq->work_time; } seq_printf(m, "SqThread:\t%d\n", sq_pid); seq_printf(m, "SqThreadCpu:\t%d\n", sq_cpu); + seq_printf(m, "SqTotalTime:\t%llu\n", sq_total_time); + seq_printf(m, "SqWorkTime:\t%llu\n", sq_work_time); seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files); for (i = 0; has_lock && i < ctx->nr_user_files; i++) { struct file *f = io_file_from_index(&ctx->file_table, i); diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c index 82672eaaee81..363052b4ea76 100644 --- a/io_uring/sqpoll.c +++ b/io_uring/sqpoll.c @@ -253,11 +253,23 @@ static bool io_sq_tw_pending(struct llist_node *retry_list) return retry_list || !llist_empty(&tctx->task_list); } +static void io_sq_update_worktime(struct io_sq_data *sqd, struct rusage *start) +{ + struct rusage end; + + getrusage(current, RUSAGE_SELF, &end); + end.ru_stime.tv_sec -= start->ru_stime.tv_sec; + end.ru_stime.tv_usec -= start->ru_stime.tv_usec; + + sqd->work_time += end.ru_stime.tv_usec + end.ru_stime.tv_sec * 1000000; +} + static int io_sq_thread(void *data) { struct llist_node *retry_list = NULL; struct io_sq_data *sqd = data; struct io_ring_ctx *ctx; + struct rusage start; unsigned long timeout = 0; char buf[TASK_COMM_LEN]; DEFINE_WAIT(wait); @@ -286,6 +298,7 @@ static int io_sq_thread(void *data) } cap_entries = !list_is_singular(&sqd->ctx_list); + getrusage(current, RUSAGE_SELF, &start); list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) { int ret = __io_sq_thread(ctx, cap_entries); @@ -296,8 +309,10 @@ static int io_sq_thread(void *data) sqt_spin = true; if (sqt_spin || !time_after(jiffies, timeout)) { - if (sqt_spin) + if (sqt_spin) { + io_sq_update_worktime(sqd, &start); timeout = jiffies + sqd->sq_thread_idle; + } if (unlikely(need_resched())) { mutex_unlock(&sqd->lock); cond_resched(); diff --git a/io_uring/sqpoll.h b/io_uring/sqpoll.h index 8df37e8c9149..4171666b1cf4 100644 --- a/io_uring/sqpoll.h +++ b/io_uring/sqpoll.h @@ -16,6 +16,7 @@ struct io_sq_data { pid_t task_pid; pid_t task_tgid; + u64 work_time; unsigned long state; struct completion exited; };