From: Jakub Kicinski <kuba@kernel.org>
To: Vishvambar Panth S <vishvambarpanth.s@microchip.com>
Cc: <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<bryan.whitehead@microchip.com>, <UNGLinuxDriver@microchip.com>,
<davem@davemloft.net>, <edumazet@google.com>, <pabeni@redhat.com>,
<andrew@lunn.ch>
Subject: Re: [PATCH net] net: microchip: lan743x : bidirectional throughuput improvement
Date: Wed, 4 Oct 2023 12:20:16 -0700 [thread overview]
Message-ID: <20231004122016.76b403f0@kernel.org> (raw)
In-Reply-To: <20230927111623.9966-1-vishvambarpanth.s@microchip.com>
On Wed, 27 Sep 2023 16:46:23 +0530 Vishvambar Panth S wrote:
> The LAN743x/PCI11xxx DMA descriptors are always 4 dwords long, but the
> device supports placing the descriptors in memory back to back or
> reserving space in between them using its DMA_DESCRIPTOR_SPACE (DSPACE)
> configurable hardware setting. Currently DSPACE is unnecessarily set to
> match the host's L1 cache line size, resulting in space reserved in
> between descriptors in most platforms and causing a suboptimal behavior
> (single PCIe Mem transaction per descriptor). By changing the setting
> to DSPACE=16 many descriptors can be packed in a single PCIe Mem
> transaction resulting in a massive performance improvement in
> bidirectional tests without any negative effects.
> Tested and verified improvements on x64 PC and several ARM platforms
> (typical data below)
Nobody complained for 5 years, and it's not a regression.
Let's not treat this as a fix, please repost without the Fixes tag for
net-next.
--
pw-bot: cr
next prev parent reply other threads:[~2023-10-04 19:20 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-27 11:16 [PATCH net] net: microchip: lan743x : bidirectional throughuput improvement Vishvambar Panth S
2023-09-29 17:35 ` Jacob Keller
2023-10-05 5:17 ` VishvambarPanth.S
2023-10-04 19:20 ` Jakub Kicinski [this message]
2023-10-04 20:02 ` Florian Fainelli
2023-10-04 20:09 ` Jakub Kicinski
2023-11-01 7:20 ` VishvambarPanth.S
2023-11-09 10:53 ` VishvambarPanth.S
2023-11-09 23:04 ` Jakub Kicinski
2023-11-16 5:49 ` VishvambarPanth.S
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