Received-SPF: pass (google.com: domain of linux-kernel+bounces-174064-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
From: "zhaoyang.huang" <zhaoyang.huang@unisoc.com>
To: Andrew Morton <akpm@linux-foundation.org>,
        Matthew Wilcox
	<willy@infradead.org>, Jens Axboe <axboe@kernel.dk>,
        Tejun Heo
	<tj@kernel.org>, Josef Bacik <josef@toxicpanda.com>,
        Baolin Wang
	<baolin.wang@linux.alibaba.com>, <linux-mm@kvack.org>,
        <linux-block@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <cgroups@vger.kernel.org>, Zhaoyang Huang <huangzhaoyang@gmail.com>,
        <steve.kang@unisoc.com>
Subject: [RFC PATCH 0/2] introduce budgt control in readahead
Date: Thu, 9 May 2024 10:39:35 +0800
Message-ID: <20240509023937.1090421-1-zhaoyang.huang@unisoc.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain

From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>

Over-limit bw value is observed during fio test in the throttling group
which caused by over-sized bio as there is no control on ra->size during
readahead. This series patches would like to introduce the helper
function to provide the bytes limit and apply it on readahead.

Please find below for the fio test result on v6.6 which presents 2%-10%
improvement for BW and lat. Besides, we can also observed stable BW
instantaneous value during the test.

blkio.throttle.read_bps_device = 1MB/s
   before:  read: IOPS=223, BW=894KiB/s (915kB/s)(175MiB/200919msec)
   after :  read: IOPS=239, BW=960KiB/s (983kB/s)(153MiB/163105msec)

   before:  clat (usec): min=4, max=16795k, avg=4468.74, stdev=265746.14
            lat  (usec): min=6, max=16795k, avg=4470.57, stdev=265746.14
   after :  clat (usec): min=11, max=209193, avg=4105.22, stdev=27188.04
            lat  (usec): min=16, max=209197, avg=4120.03, stdev=27188.04


blkio.throttle.read_bps_device = 10MB/s
   before:  read: IOPS=2380, BW=9524KiB/s (9752kB/s)(1007MiB/108311msec)
   after :  read: IOPS=2438, BW=9754KiB/s (9989kB/s)(1680MiB/176405msec)

   before:  clat (usec): min=4, max=201817, avg=399.58, stdev=8268.85
            lat  (usec): min=6, max=201819, avg=402.10, stdev=8268.85
   after :  clat (usec): min=4, max=2494.6k, avg=412.72, stdev=25783.51
            lat  (usec): min=6, max=2494.6k, avg=414.48, stdev=25783.51

Zhaoyang Huang (2):
  block: introduce helper function to calculate bps budgt
  mm: introduce budgt control in readahead

 block/blk-throttle.c       | 44 ++++++++++++++++++++++++++++++++++++++
 include/linux/blk-cgroup.h | 10 +++++++++
 mm/readahead.c             | 33 ++++++++++++++++++++--------
 3 files changed, 78 insertions(+), 9 deletions(-)

-- 
2.25.1