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net: mvneta: set real interrupt per packet for tx_done 

Commit aebea2ba0f ("net: mvneta: fix Tx interrupt delay") intended to
set coalescing threshold to a value guaranteeing interrupt generation
per each sent packet, so that buffers can be released with no delay.

In fact setting threshold to '1' was wrong, because it causes interrupt
every two packets. According to the documentation a reason behind it is
following - interrupt occurs once sent buffers counter reaches a value,
which is higher than one specified in MVNETA_TXQ_SIZE_REG(q). This
behavior was confirmed during tests. Also when testing the SoC working
as a NAS device, better performance was observed with int-per-packet,
as it strongly depends on the fact that all transmitted packets are
released immediately.

This commit enables NETA controller work in interrupt per sent packet mode
by setting coalescing threshold to 0.

Signed-off-by: Dmitri Epshtein <dima@marvell.com>
Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Cc: <stable@vger.kernel.org> # v3.10+
Fixes aebea2ba0f ("net: mvneta: fix Tx interrupt delay")
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Dmitri Epshtein 2016-07-06 04:18:58 +02:00 committed by David S. Miller
parent bc86765181
commit 06708f8152
1 changed files with 1 additions and 1 deletions
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2
drivers/net/ethernet/marvell/mvneta.c
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@ -244,7 +244,7 @@
/* Various constants */
/* Coalescing */
#define MVNETA_TXDONE_COAL_PKTS 1
#define MVNETA_TXDONE_COAL_PKTS 0 /* interrupt per packet */
#define MVNETA_RX_COAL_PKTS 32
#define MVNETA_RX_COAL_USEC 100