Re: Re: [PATCH v9] io_uring: Statistics of the true utilization of sq threads.

[Xiaobing Li <xiaobing.li@samsung.com>]

On 2/21/24 10:28, Jens Axboe wrote:
>On 2/20/24 7:04 PM, Xiaobing Li wrote:
>> On 2/19/24 14:42, Xiaobing Li wrote:
>>> 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 65b5dbe3c850..006d7fc9cf92 100644
>>> --- a/io_uring/sqpoll.c
>>> +++ b/io_uring/sqpoll.c
>>> @@ -219,10 +219,22 @@ static bool io_sqd_handle_event(struct io_sq_data *sqd)
>>> 	return did_sig || test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
>>> }
>>>
>>> +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 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);
>>> @@ -251,6 +263,7 @@ 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);
>>>
>>> @@ -261,8 +274,10 @@ 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;
>>> };
>>  
>> Hi, Jens
>> I have modified the code according to your suggestions.
>> Do you have any other comments?
>
>Out of town this week, I'll check next week. But from a quick look,
>looks much better now.
 
Hi, Jens
Do you have time to check now?

--
Xiaobing Li