Module Name: src
Committed By: msaitoh
Date: Wed Sep 8 09:09:47 UTC 2021
Modified Files:
src/sys/dev/pci/ixgbe: ix_txrx.c
Log Message:
Reduce bus_dmamap_sync() cost.
- Don't sync whole descriptor ring but limited counts(rx_process_limit)
descriptors.
- Dont' sync every loop.
To generate a diff of this commit:
cvs rdiff -u -r1.93 -r1.94 src/sys/dev/pci/ixgbe/ix_txrx.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/pci/ixgbe/ix_txrx.c
diff -u src/sys/dev/pci/ixgbe/ix_txrx.c:1.93 src/sys/dev/pci/ixgbe/ix_txrx.c:1.94
--- src/sys/dev/pci/ixgbe/ix_txrx.c:1.93 Wed Sep 8 08:46:28 2021
+++ src/sys/dev/pci/ixgbe/ix_txrx.c Wed Sep 8 09:09:47 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: ix_txrx.c,v 1.93 2021/09/08 08:46:28 msaitoh Exp $ */
+/* $NetBSD: ix_txrx.c,v 1.94 2021/09/08 09:09:47 msaitoh Exp $ */
/******************************************************************************
@@ -64,7 +64,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ix_txrx.c,v 1.93 2021/09/08 08:46:28 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ix_txrx.c,v 1.94 2021/09/08 09:09:47 msaitoh Exp $");
#include "opt_inet.h"
#include "opt_inet6.h"
@@ -1804,9 +1804,11 @@ ixgbe_rxeof(struct ix_queue *que)
struct ixgbe_rx_buf *rbuf, *nbuf;
int i, nextp, processed = 0;
u32 staterr = 0;
- u32 loopcount = 0;
+ u32 loopcount = 0, numdesc;
u32 limit = adapter->rx_process_limit;
bool discard_multidesc = rxr->discard_multidesc;
+ bool wraparound = false;
+ unsigned int syncremain;
#ifdef RSS
u16 pkt_info;
#endif
@@ -1823,6 +1825,24 @@ ixgbe_rxeof(struct ix_queue *que)
}
#endif /* DEV_NETMAP */
+ /* Sync the ring. The size is rx_process_limit or the first half */
+ if ((rxr->next_to_check + limit) <= rxr->num_desc) {
+ /* Non-wraparound */
+ numdesc = limit;
+ syncremain = 0;
+ } else {
+ /* Wraparound. Sync the first half. */
+ numdesc = rxr->num_desc - rxr->next_to_check;
+
+ /* Set the size of the last half */
+ syncremain = limit - numdesc;
+ }
+ bus_dmamap_sync(rxr->rxdma.dma_tag->dt_dmat,
+ rxr->rxdma.dma_map,
+ sizeof(union ixgbe_adv_rx_desc) * rxr->next_to_check,
+ sizeof(union ixgbe_adv_rx_desc) * numdesc,
+ BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
+
/*
* The max number of loop is rx_process_limit. If discard_multidesc is
* true, continue processing to not to send broken packet to the upper
@@ -1839,9 +1859,22 @@ ixgbe_rxeof(struct ix_queue *que)
bool eop;
bool discard = false;
- /* Sync the ring. */
- ixgbe_dmamap_sync(rxr->rxdma.dma_tag, rxr->rxdma.dma_map,
- BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
+ if (wraparound) {
+ /* Sync the last half. */
+ KASSERT(syncremain != 0);
+ numdesc = syncremain;
+ wraparound = false;
+ } else if (__predict_false(loopcount >= limit)) {
+ KASSERT(discard_multidesc == true);
+ numdesc = 1;
+ } else
+ numdesc = 0;
+
+ if (numdesc != 0)
+ bus_dmamap_sync(rxr->rxdma.dma_tag->dt_dmat,
+ rxr->rxdma.dma_map, 0,
+ sizeof(union ixgbe_adv_rx_desc) * numdesc,
+ BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
cur = &rxr->rx_base[i];
staterr = le32toh(cur->wb.upper.status_error);
@@ -2105,8 +2138,10 @@ next_desc:
BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
/* Advance our pointers to the next descriptor. */
- if (++i == rxr->num_desc)
+ if (++i == rxr->num_desc) {
+ wraparound = true;
i = 0;
+ }
rxr->next_to_check = i;
/* Now send to the stack or do LRO */
