linux-kernel - Re: [PATCH] block:genhd:/proc/diskstats: use seq_put_decimal

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Message-Id: <173153180276.2249291.10428535421528000816.b4-ty@kernel.dk>
Date: Wed, 13 Nov 2024 14:03:22 -0700
From: Jens Axboe <axboe@...nel.dk>
To: David Wang <00107082@....com>
Cc: linux-block@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] block:genhd:/proc/diskstats: use seq_put_decimal_ull
 for decimal values


On Fri, 08 Nov 2024 13:45:00 +0800, David Wang wrote:
> seq_printf is costy, for each block device, 19 decimal values are
> yielded in /proc/diskstats via seq_printf; On a system with 16
> logical block devices, profiling for open/read/close sequences
> shows seq_printf took ~75% samples of diskstats_show:
> 
> 	diskstats_show(92.626% 2269372/2450040)
> 	    seq_printf(76.026% 1725313/2269372)
> 		vsnprintf(99.163% 1710866/1725313)
> 		    format_decode(26.597% 455040/1710866)
> 		    number(19.554% 334542/1710866)
> 		    memcpy_orig(4.183% 71570/1710866)
> 			...
> 		srso_return_thunk(0.009% 148/1725313)
> 	    part_stat_read_all(8.030% 182236/2269372)
> 
> [...]

Applied, thanks!

[1/1] block:genhd:/proc/diskstats: use seq_put_decimal_ull for decimal values
      commit: bda9c7d92f24b693eaf0262c090de4c8c108a28e

Best regards,
-- 
Jens Axboe