diff mbox series

[net,3/5] net: sparx5: fix FDMA performance issue

Message ID 20241205-sparx5-lan969x-misc-fixes-v1-3-575ff3d0b022@microchip.com (mailing list archive)
State Accepted
Commit f004f2e535e2b66ccbf5ac35f8eaadeac70ad7b7
Delegated to: Netdev Maintainers
Headers show
Series net: sparx5: misc fixes for sparx5 and lan969x | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 10 of 10 maintainers
netdev/build_clang success Errors and warnings before: 3 this patch: 3
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 304 this patch: 304
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 17 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-12-06--18-00 (tests: 764)

Commit Message

Daniel Machon Dec. 5, 2024, 1:54 p.m. UTC
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@microchip.com>
---
 drivers/net/ethernet/microchip/sparx5/sparx5_main.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_main.c b/drivers/net/ethernet/microchip/sparx5/sparx5_main.c
index 2b58fcb9422e..f61aa15beab7 100644
--- a/drivers/net/ethernet/microchip/sparx5/sparx5_main.c
+++ b/drivers/net/ethernet/microchip/sparx5/sparx5_main.c
@@ -780,12 +780,11 @@  static int sparx5_start(struct sparx5 *sparx5)
 	err = -ENXIO;
 	if (sparx5->fdma_irq >= 0 && is_sparx5(sparx5)) {
 		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)