diff options
| author | Jesper Dangaard Brouer <brouer@redhat.com> | 2016-11-03 14:56:01 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-11-07 20:15:55 -0500 |
| commit | d0a81f67cd6286d32f42a167d19c7a387c23db79 (patch) | |
| tree | 6f0916931fbabec1fa375adf6df254baa72408d9 | |
| parent | fc13fd3986257882a69581c3c8203221053f474d (diff) | |
net: make default TX queue length a defined constant
The default TX queue length of Ethernet devices have been a magic
constant of 1000, ever since the initial git import.
Looking back in historical trees[1][2] the value used to be 100,
with the same comment "Ethernet wants good queues". The commit[3]
that changed this from 100 to 1000 didn't describe why, but from
conversations with Robert Olsson it seems that it was changed
when Ethernet devices went from 100Mbit/s to 1Gbit/s, because the
link speed increased x10 the queue size were also adjusted. This
value later caused much heartache for the bufferbloat community.
This patch merely moves the value into a defined constant.
[1] https://git.kernel.org/cgit/linux/kernel/git/davem/netdev-vger-cvs.git/
[2] https://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/
[3] https://git.kernel.org/tglx/history/c/98921832c232
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/pkt_sched.h | 2 | ||||
| -rw-r--r-- | net/ethernet/eth.c | 3 |
2 files changed, 4 insertions, 1 deletions
diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h index cd334c9584e9..f1b76b8e6d2d 100644 --- a/include/net/pkt_sched.h +++ b/include/net/pkt_sched.h @@ -6,6 +6,8 @@ #include <linux/if_vlan.h> #include <net/sch_generic.h> +#define DEFAULT_TX_QUEUE_LEN 1000 + struct qdisc_walker { int stop; int skip; diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c index d9e2fe1da724..8c5a479681ca 100644 --- a/net/ethernet/eth.c +++ b/net/ethernet/eth.c @@ -62,6 +62,7 @@ #include <net/dsa.h> #include <net/flow_dissector.h> #include <linux/uaccess.h> +#include <net/pkt_sched.h> __setup("ether=", netdev_boot_setup); @@ -359,7 +360,7 @@ void ether_setup(struct net_device *dev) dev->min_mtu = ETH_MIN_MTU; dev->max_mtu = ETH_DATA_LEN; dev->addr_len = ETH_ALEN; - dev->tx_queue_len = 1000; /* Ethernet wants good queues */ + dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN; dev->flags = IFF_BROADCAST|IFF_MULTICAST; dev->priv_flags |= IFF_TX_SKB_SHARING; |