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From: Lukas Wunner <lukas@wunner.de>
To: Graham Whyte <grwhyte@linux.microsoft.com>
Cc: linux-pci@vger.kernel.org, shyamsaini@linux.microsoft.com,
	code@tyhicks.com, Okaya@kernel.org, bhelgaas@google.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] PCI: Reduce delay after FLR of Microsoft MANA devices
Date: Sat, 31 May 2025 16:09:09 +0200	[thread overview]
Message-ID: <aDsNhVIv5xt3S7KQ@wunner.de> (raw)
In-Reply-To: <b23fb8f4-0da7-4403-8a2d-665d5675be9c@linux.microsoft.com>

On Fri, May 30, 2025 at 09:26:16AM -0700, Graham Whyte wrote:
> On 5/29/2025 3:34 AM, Lukas Wunner wrote:
> > On Wed, May 28, 2025 at 06:10:47PM +0000, grwhyte@linux.microsoft.com wrote:
> > > Add a device-specific reset for Microsoft MANA devices with the FLR
> > > delay reduced from 100ms to 10ms. While this is not compliant with the
> > > pci spec, these devices safely complete the FLR much quicker than 100ms
> > > and this can be reduced to optimize certain scenarios
> > 
> > How often do you reset these devices that 90 msec makes a difference?
> > What are these "certain scenarios"?
> 
> VF removal and rescan is the main scenario for runtime repairs and driver
> updates.
> Doing this on scale with 100ms adds up to significant time across multiple
> VFs.

Please mention this in the commit message to avoid head-scratching
by someone reading it down the road.

Thanks,

Lukas

      reply	other threads:[~2025-05-31 14:09 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-28 18:10 [PATCH v2] PCI: Reduce delay after FLR of Microsoft MANA devices grwhyte
2025-05-29 10:34 ` Lukas Wunner
2025-05-30 16:26   ` Graham Whyte
2025-05-31 14:09     ` Lukas Wunner [this message]

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