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

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Message-ID: <94284465-0b46-4df4-842e-a0c65dee5908@kernel.dk>
Date: Tue, 27 Feb 2024 07:36:52 -0700
From: Jens Axboe <axboe@...nel.dk>
To: Xiaobing Li <xiaobing.li@...sung.com>
Cc: asml.silence@...il.com, linux-kernel@...r.kernel.org,
 io-uring@...r.kernel.org, kun.dou@...sung.com, peiwei.li@...sung.com,
 joshi.k@...sung.com, kundan.kumar@...sung.com, wenwen.chen@...sung.com,
 ruyi.zhang@...sung.com, cliang01.li@...sung.com, xue01.he@...sung.com
Subject: Re: [PATCH v9] io_uring: Statistics of the true utilization of sq
 threads.

On 2/26/24 10:45 PM, Xiaobing Li wrote:
> 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?

Can I ask you to resend it against for-6.9/io_uring? For some reason I
don't see the original patch on the list.

-- 
Jens Axboe