Re: Scrub of my nvme SSD has slowed by about 2/3

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

On 2023/9/8 19:54, Martin Steigerwald wrote:
> Hi Thorsten, Qu, Tim, everyone,
>
> Linux regression tracking #update (Thorsten Leemhuis) - 29.08.23, 14:17:33
> CEST:
>> On 12.07.23 13:02, Linux regression tracking #adding (Thorsten Leemhuis)
>> wrote:
>>> On 03.07.23 22:19, Tim Cuthbertson wrote:
>>>> Yesterday, I noticed that a scrub of my main system filesystem has
>>>> slowed from about 2.9 gb/sec to about 949 mb/sec. My scrub used to
>>>> run
>>>> in about 12 seconds, now it is taking 51 seconds. I had just
>>>> installed
>>>> Linux kernel 6.4.1 on Arch Linux, upgrading from 6.3.9. At first I
>>>> suspected the new kernel, but now I am not so sure.
>>>
>>> Thanks for the report. It seems it will take some work to address
>>> this,
>>> so to be sure the issue doesn't fall through the cracks unnoticed, I'm
>>> adding it to regzbot, the Linux kernel regression tracking bot:
>>>
>>> #regzbot ^introduced e02ee89baa66
>>
>> #regzbot resolve: various changes merged for 6.6 improve things again;
>> more planned; backporting is planned, too;
>> #regzbot ignore-activity
>>
>> (yes, that is not idea, but that's how it is sometimes)
>
> ideal?
>
> Scrubbing "/home" with 304.61GiB (interestingly both back then with 6.4
> and now with 6.5.2):
>
> - 6.4: 966.84MiB/s
> - 6.5.2:  748.02MiB/s
>
> I expected an improvement.
>
> Same Lenovo ThinkPad T14 AMD Gen 1 with AMD Ryzen 7 PRO 4750U, 32 GiB RAM
> and 2TB Samsung 980 Pro NVME SSD as before.

The fixes didn't arrive until v6.6.

Thanks,
Qu

>
> Ciao,