6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Daniel Machon <daniel.machon@xxxxxxxxxxxxx>
[ 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>
---
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 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)
--
2.39.5
