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Date: Mon, 25 Mar 2024 12:06:16 +0000
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Subject: Re: [RFC PATCH 0/2] Introduce per-task io utilization boost
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To: Bart Van Assche <bvanassche@acm.org>, Qais Yousef <qyousef@layalina.io>
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
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From: Christian Loehle <christian.loehle@arm.com>
In-Reply-To: <2ed2dadc-bdc4-4a21-8aca-a2aac0c6479a@acm.org>
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On 21/03/2024 19:52, Bart Van Assche wrote:
> On 3/21/24 10:57, Christian Loehle wrote:
>> In the long-term it looks like for UFS the problem will disappear as we are
>> expected to get one queue/hardirq per CPU (as Bart mentioned), on NVMe that
>> is already the case.
> 
> Why the focus on storage controllers with a single completion interrupt?
> It probably won't take long (one year?) until all new high-end
> smartphones may have support for multiple completion interrupts.
> 
> Thanks,
> 
> Bart.
> 

Apart from going to "This patch shows significant performance improvements on
hardware that runs mainline today" to "This patch will have significant
performance improvements on devices running mainline in a couple years"
nothing in particular.
I'm fine with leaving it with having acknowledged the problem.
Maybe I would just gate the task placement on the task having been in
UFS (with multiple completion interrupts) or NVMe submission recently to
avoid regressions to current behavior in future versions. I did have that
already at some point, although it was a bit hacky.
Anyway, thank you for your input on that, it is what I wanted to hear!

Kind Regards,
Christian