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From: Pavel Begunkov <[email protected]>
To: Olivier Langlois <[email protected]>,
	Jens Axboe <[email protected]>,
	[email protected]
Subject: Re: [PATCH] io_uring: add napi busy settings to the fdinfo output
Date: Tue, 30 Jul 2024 16:33:36 +0100	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <bb184f8b62703ddd3e6e19eae7ab6c67b97e1e10.1722293317.git.olivier@trillion01.com>

On 7/29/24 23:38, Olivier Langlois wrote:
> this info may be useful when attempting to debug a problem
> involving a ring using the feature.

While on the topic of busy polling, there is a function
io_napi_adjust_timeout(), it ensures that we don't busy poll for longer
than the passed wait timeout.

Do you use it? I have some doubts in regards to its usefulness, and
would prefer to try get rid of it if there are no users since it's a
hustle.


> CqOverflowList:
> NAPI:	enabled
> napi_busy_poll_to:	1
> napi_prefer_busy_poll:	true
> 
> Signed-off-by: Olivier Langlois <[email protected]>
> ---
>   io_uring/fdinfo.c | 13 ++++++++++++-
>   1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/io_uring/fdinfo.c b/io_uring/fdinfo.c
> index b1e0e0d85349..3ba42e136a40 100644
> --- a/io_uring/fdinfo.c
> +++ b/io_uring/fdinfo.c
> @@ -221,7 +221,18 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *file)
>   			   cqe->user_data, cqe->res, cqe->flags);
>   
>   	}
> -
> +#ifdef CONFIG_NET_RX_BUSY_POLL
> +	if (ctx->napi_enabled) {
> +		seq_puts(m, "NAPI:\tenabled\n");
> +		seq_printf(m, "napi_busy_poll_dt:\t%llu\n", ctx->napi_busy_poll_dt);
> +		if (ctx->napi_prefer_busy_poll)
> +			seq_puts(m, "napi_prefer_busy_poll:\ttrue\n");
> +		else
> +			seq_puts(m, "napi_prefer_busy_poll:\tfalse\n");
> +	} else {
> +		seq_puts(m, "NAPI:\tdisabled\n");
> +	}
> +#endif
>   	spin_unlock(&ctx->completion_lock);
>   }
>   #endif

-- 
Pavel Begunkov

  parent reply	other threads:[~2024-07-30 15:33 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-29 22:38 [PATCH] io_uring: add napi busy settings to the fdinfo output Olivier Langlois
2024-07-30 11:05 ` Pavel Begunkov
2024-07-30 14:04   ` Olivier Langlois
2024-07-30 14:08     ` Pavel Begunkov
2024-07-30 14:46       ` Jens Axboe
2024-07-30 12:26 ` Jens Axboe
2024-07-30 15:33 ` Pavel Begunkov [this message]
2024-07-30 15:38   ` Pavel Begunkov
2024-07-30 19:05   ` Olivier Langlois

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