| Message ID | 20250319-igc-fix-tx-zero-copy-drops-v1-1-d90bc63a4dc4@siemens.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] igc: Fix TX drops in XDP ZC | expand |
On Wednesday, March 19, 2025 10:19 PM, Zdenek Bouska <zdenek.bouska@siemens.com> wrote: >Fixes TX frame drops in AF_XDP zero copy mode when budget < 4. >xsk_tx_peek_desc() consumed TX frame and it was ignored because of >low budget. Not even AF_XDP completion was done for dropped frames. > >It can be reproduced on i226 by sending 100000x 60 B frames with >launch time set to minimal IPG (672 ns between starts of frames) >on 1Gbit/s. Always 1026 frames are not sent and are missing a >completion. > >Fixes: 9acf59a752d4c ("igc: Enable TX via AF_XDP zero-copy") >Signed-off-by: Zdenek Bouska <zdenek.bouska@siemens.com> Reviewed-by: Song Yoong Siang <yoong.siang.song@intel.com> >--- > drivers/net/ethernet/intel/igc/igc_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > >diff --git a/drivers/net/ethernet/intel/igc/igc_main.c >b/drivers/net/ethernet/intel/igc/igc_main.c >index 472f009630c9..f2e0a30a3497 100644 >--- a/drivers/net/ethernet/intel/igc/igc_main.c >+++ b/drivers/net/ethernet/intel/igc/igc_main.c >@@ -3042,7 +3042,7 @@ static void igc_xdp_xmit_zc(struct igc_ring *ring) > * descriptors. Therefore, to be safe, we always ensure we have at least > * 4 descriptors available. > */ >- while (xsk_tx_peek_desc(pool, &xdp_desc) && budget >= 4) { >+ while (budget >= 4 && xsk_tx_peek_desc(pool, &xdp_desc)) { > struct igc_metadata_request meta_req; > struct xsk_tx_metadata *meta = NULL; > struct igc_tx_buffer *bi; > >--- >base-commit: 8ef890df4031121a94407c84659125cbccd3fdbe >change-id: 20250310-igc-fix-tx-zero-copy-drops-1c4a81441033 > >Best regards, >-- >Zdenek Bouska > >Siemens, s.r.o. >Foundational Technologies
On Wed, 2025-03-19 at 15:18 +0100, Zdenek Bouska wrote: > Fixes TX frame drops in AF_XDP zero copy mode when budget < 4. > xsk_tx_peek_desc() consumed TX frame and it was ignored because of > low budget. Not even AF_XDP completion was done for dropped frames. > > It can be reproduced on i226 by sending 100000x 60 B frames with > launch time set to minimal IPG (672 ns between starts of frames) > on 1Gbit/s. Always 1026 frames are not sent and are missing a > completion. > > Fixes: 9acf59a752d4c ("igc: Enable TX via AF_XDP zero-copy") > Signed-off-by: Zdenek Bouska <zdenek.bouska@siemens.com> Reviewed-by: Florian Bezdeka <florian.bezdeka@siemens.com> > --- > drivers/net/ethernet/intel/igc/igc_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c > index 472f009630c9..f2e0a30a3497 100644 > --- a/drivers/net/ethernet/intel/igc/igc_main.c > +++ b/drivers/net/ethernet/intel/igc/igc_main.c > @@ -3042,7 +3042,7 @@ static void igc_xdp_xmit_zc(struct igc_ring *ring) > * descriptors. Therefore, to be safe, we always ensure we have at least > * 4 descriptors available. > */ > - while (xsk_tx_peek_desc(pool, &xdp_desc) && budget >= 4) { > + while (budget >= 4 && xsk_tx_peek_desc(pool, &xdp_desc)) { > struct igc_metadata_request meta_req; > struct xsk_tx_metadata *meta = NULL; > struct igc_tx_buffer *bi; > > --- > base-commit: 8ef890df4031121a94407c84659125cbccd3fdbe > change-id: 20250310-igc-fix-tx-zero-copy-drops-1c4a81441033 > > Best regards, > -- > Zdenek Bouska > > Siemens, s.r.o. > Foundational Technologies
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c index 472f009630c9..f2e0a30a3497 100644 --- a/drivers/net/ethernet/intel/igc/igc_main.c +++ b/drivers/net/ethernet/intel/igc/igc_main.c @@ -3042,7 +3042,7 @@ static void igc_xdp_xmit_zc(struct igc_ring *ring) * descriptors. Therefore, to be safe, we always ensure we have at least * 4 descriptors available. */ - while (xsk_tx_peek_desc(pool, &xdp_desc) && budget >= 4) { + while (budget >= 4 && xsk_tx_peek_desc(pool, &xdp_desc)) { struct igc_metadata_request meta_req; struct xsk_tx_metadata *meta = NULL; struct igc_tx_buffer *bi;
Fixes TX frame drops in AF_XDP zero copy mode when budget < 4. xsk_tx_peek_desc() consumed TX frame and it was ignored because of low budget. Not even AF_XDP completion was done for dropped frames. It can be reproduced on i226 by sending 100000x 60 B frames with launch time set to minimal IPG (672 ns between starts of frames) on 1Gbit/s. Always 1026 frames are not sent and are missing a completion. Fixes: 9acf59a752d4c ("igc: Enable TX via AF_XDP zero-copy") Signed-off-by: Zdenek Bouska <zdenek.bouska@siemens.com> --- drivers/net/ethernet/intel/igc/igc_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: 8ef890df4031121a94407c84659125cbccd3fdbe change-id: 20250310-igc-fix-tx-zero-copy-drops-1c4a81441033 Best regards,