[PATCH V3 0/2] Add CPU latency QoS support for ufs driver

From: Maramaina Naresh
Date: Tue Dec 12 2023 - 06:56:23 EST


Add CPU latency QoS support for ufs driver. This improves random io
performance by 15% for ufs.

tiotest benchmark tool io performance results on sm8550 platform:

1. Without PM QoS support
Type (Speed in) | Average of 18 iterations
Random Read(IPOS) | 37101.3
Random Write(IPOS) | 41065.13

2. With PM QoS support
Type (Speed in) | Average of 18 iterations
Random Read(IPOS) | 42943.4
Random Write(IPOS) | 46784.9
(Improvement with PM QoS = ~15%).

This patch is based on below patch by Stanley Chu [1].
Moving the PM QoS code to ufshcd.c and making it generic.

[1] https://lore.kernel.org/r/20220623035052.18802-8-stanley.chu@xxxxxxxxxxxx

Changes from v2:
- Addressed bvanassche and mani comments
- Provided sysfs interface to enable/disable PM QoS feature

Changes from v1:
- Addressed bvanassche comments to have the code in core ufshcd
- Design is changed from per-device PM QoS to CPU latency QoS based support
- Reverted existing PM QoS feature from MEDIATEK UFS driver

Maramaina Naresh (2):
ufs: core: Add CPU latency QoS support for ufs driver
ufs: ufs-mediatek: Enable CPU latency PM QoS support for MEDIATEK SoC

drivers/ufs/core/ufshcd.c | 127 ++++++++++++++++++++++++++++++++
drivers/ufs/host/ufs-mediatek.c | 20 +----
drivers/ufs/host/ufs-mediatek.h | 3 -
include/ufs/ufshcd.h | 6 ++
4 files changed, 136 insertions(+), 20 deletions(-)

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2.17.1