Re: [RFC 0/1] writeback: add sysfs to config the number of writeback contexts

[Kundan Kumar]

On 8/25/2025 5:59 PM, wangyufei wrote:
> Hi everyone,
> 
> We've been interested in this patch about parallelizing writeback [1]
> and have been following its discussion and development. Our testing in
> several application scenarios on mobile devices has shown significant
> performance improvements.
> 

Hi,

Thanks for sharing this work.

Could you clarify a few details about your test setup?

- Which filesystem did you run these experiments on?
- What were the specifics of the workload (number of threads, block size,
   I/O size)?
- If you are using fio, can you please share the fio command.
- How much RAM was available on the test system?
- Can you share the performance improvement numbers you observed?

That would help in understanding the impact of parallel writeback?

I made similar modifications to dynamically configure the number of
writeback threads in this experimental patch. Refer to patches 14 and 15:
https://lore.kernel.org/all/20250807045706.2848-1-kundan.kumar@xxxxxxxxxxx/
The key difference is that this change also enables a reduction in the
number of writeback threads.

Thanks,
Kundan

>