Performance tuning.

Moved the RX ring resyncing code to ste_rxeoc(), and only run it
if we were asked to POLL_AND_CHECK_STATUS, under DEVICE_POLLING.
(This significantly reduces the CPU load.)

Improved the RX ring resyncing code by re-checking if the head
is still empty before doing resyncing.  This mostly affects the
DEVICE_POLLING mode, where we run this code periodically.  We
could start checking with an empty head (well, an empty ring
even), and after doing a few iterations, the chip might write
a few entries, including the head, and we would bogusly consider
this case as requiring resyncing.  On a test box, this reduced
the number of resyncs done by a factor of 10.

In ste_txeof(sc), only reset the watchdog timer to zero when
the TX list is completely empty.

Converted ste_tx_prev_idx to a pointer -- faster.

Removed some bitrot.

1 files changed, 1 insertions, 3 deletions

diff --git a/sys/pci/if_stereg.h b/sys/pci/if_stereg.h
index 0de4f78d..90350b4 100644
--- a/sys/pci/if_stereg.h
+++ b/sys/pci/if_stereg.h
@@ -479,14 +479,12 @@ struct ste_type {
 struct ste_list_data {
 	struct ste_desc_onefrag	ste_rx_list[STE_RX_LIST_CNT];
 	struct ste_desc		ste_tx_list[STE_TX_LIST_CNT];
-	u_int8_t		ste_pad[STE_MIN_FRAMELEN];
 };
 
 struct ste_chain {
 	struct ste_desc		*ste_ptr;
 	struct mbuf		*ste_mbuf;
 	struct ste_chain	*ste_next;
-	struct ste_chain	*ste_prev;
 	u_int32_t		ste_phys;
 };
 
@@ -520,7 +518,7 @@ struct ste_softc {
 	int			ste_tx_thresh;
 	u_int8_t		ste_link;
 	int			ste_if_flags;
-	int			ste_tx_prev_idx;
+	struct ste_chain	*ste_tx_prev;
 	struct ste_list_data	*ste_ldata;
 	struct ste_chain_data	ste_cdata;
 	struct callout_handle	ste_stat_ch;