This is a note to let you know that I've just added the patch titled net: sparx5: fix FDMA performance issue to the 6.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-sparx5-fix-fdma-performance-issue.patch and it can be found in the queue-6.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit a88ee71e3f41551e49fe44d175c37615293dc490 Author: Daniel Machon <daniel.machon@xxxxxxxxxxxxx> Date: Thu Dec 5 14:54:26 2024 +0100 net: sparx5: fix FDMA performance issue [ Upstream commit f004f2e535e2b66ccbf5ac35f8eaadeac70ad7b7 ] The FDMA handler is responsible for scheduling a NAPI poll, which will eventually fetch RX packets from the FDMA queue. Currently, the FDMA handler is run in a threaded context. For some reason, this kills performance. Admittedly, I did not do a thorough investigation to see exactly what causes the issue, however, I noticed that in the other driver utilizing the same FDMA engine, we run the FDMA handler in hard IRQ context. Fix this performance issue, by running the FDMA handler in hard IRQ context, not deferring any work to a thread. Prior to this change, the RX UDP performance was: Interval Transfer Bitrate Jitter 0.00-10.20 sec 44.6 MBytes 36.7 Mbits/sec 0.027 ms After this change, the rx UDP performance is: Interval Transfer Bitrate Jitter 0.00-9.12 sec 1.01 GBytes 953 Mbits/sec 0.020 ms Fixes: 10615907e9b5 ("net: sparx5: switchdev: adding frame DMA functionality") Signed-off-by: Daniel Machon <daniel.machon@xxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_main.c b/drivers/net/ethernet/microchip/sparx5/sparx5_main.c index b64c814eac11..0c4c75b3682f 100644 --- a/drivers/net/ethernet/microchip/sparx5/sparx5_main.c +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_main.c @@ -693,12 +693,11 @@ static int sparx5_start(struct sparx5 *sparx5) err = -ENXIO; if (sparx5->fdma_irq >= 0) { if (GCB_CHIP_ID_REV_ID_GET(sparx5->chip_id) > 0) - err = devm_request_threaded_irq(sparx5->dev, - sparx5->fdma_irq, - NULL, - sparx5_fdma_handler, - IRQF_ONESHOT, - "sparx5-fdma", sparx5); + err = devm_request_irq(sparx5->dev, + sparx5->fdma_irq, + sparx5_fdma_handler, + 0, + "sparx5-fdma", sparx5); if (!err) err = sparx5_fdma_start(sparx5); if (err)