From 56dff50d4f228b1ca71cb97a3886c1d28bdbdea6 Mon Sep 17 00:00:00 2001 From: Daniel Machon Date: Thu, 13 Mar 2025 13:21:44 +0900 Subject: [PATCH] net: sparx5: fix FDMA performance issue BugLink: https://bugs.launchpad.net/bugs/2102181 [ 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 Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Koichiro Den Signed-off-by: Mehmet Basaran --- drivers/net/ethernet/microchip/sparx5/sparx5_main.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_main.c b/drivers/net/ethernet/microchip/sparx5/sparx5_main.c index 3c066b62e689..51a725b20c14 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)