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From: Bagas Sanjaya <>
To: Ping-Ke Shih <>, Kalle Valo <>,
	Brett Hassall <>
Cc: Linux Kernel Mailing List <>,
	Linux Wireless <>,
	Linux Regressions <>
Subject: Fwd: 5c8a79e8e12b ("wifi: rtw88: correct PS calculation for SUPPORTS_DYNAMIC_PS", 2023-05-27) increases CPU usage usage for irq
Date: Sun, 27 Aug 2023 09:37:21 +0700	[thread overview]
Message-ID: <> (raw)


I notice a regression report on Bugzilla [1]. Quoting from it:

> This commit improves power saving - it enables the kernel to achieve package C8. To achieve package C8, 3 Ubuntu VMD commits must be applied as well. The combined patch for the 3 Ubuntu VMD commits is attached (just in case). Package C8 lowers power usage on the laptop from 5.6W to 2.6W.
> However, a side-effect of this commit is that CPU usage for irq/155-rtw88_pci has increased noticeably. This commit was introduced in 6.4-rc6. To confirm this commit is the cause, a branch was created from 6.4-rc5. This commit and the 3 Ubuntu VMD commits were applied. The resulting kernel was built and tested - it can achieve package C8 and exhibits the increased CPU usage on irq/155-rtw88_pci.
> Booting and running top for 30 min with the system otherwise idle, gives these results for CPU on irq/155-rtw88_pci:
> 6.4-rc5     - 00:02.9, mostly   0% and 0.3% displayed
> patched rc5 - 00:13.4, mostly 0.7% and 1.0% displayed
> By comparison, an 8th Gen Dell with an Intel WIFI has CPU usage of 00:01.7 under the same conditions.
> Laptop is a HP 15s-fq4011TU 11th Gen (Tiger Lake) Intel with (from lspci) Realtek Semiconductor Co., Ltd. RTL8822CE 802.11ac PCIe Wireless Network Adapter and Intel Corporation Volume Management Device NVMe RAID Controller.
> Ubuntu bug provides further background.
> Please advise if I can assist with further testing.

See Bugzilla for the full thread and attached proposed patch(es) that fix
this regression.

Anyway, I'm adding this regression to be tracked by regzbot:

#regzbot introduced: 26a125f550a3bf
#regzbot title: correcting SUPPORTS_DYNAMIC_PS calculation for rtw88 increases CPU utilization
#regzbot link:



An old man doll... just what I always wanted! - Clara

             reply	other threads:[~2023-08-27  2:38 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-27  2:37 Bagas Sanjaya [this message]
2023-09-11 13:29 ` Fwd: 5c8a79e8e12b ("wifi: rtw88: correct PS calculation for SUPPORTS_DYNAMIC_PS", 2023-05-27) increases CPU usage usage for irq Linux regression tracking (Thorsten Leemhuis)
2023-09-15 23:04   ` brett hassall
2023-09-20 14:09     ` Thorsten Leemhuis
2023-09-22 20:52       ` brett hassall

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