diff options
author | Eric Dumazet <dada1@cosmosbay.com> | 2009-05-18 00:34:33 (GMT) |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2009-05-18 22:15:06 (GMT) |
commit | 7004bf252c53da18f6b55103e0c92f777f846806 (patch) | |
tree | 29868ce170599fbed3471f53afe3a20f23fb31c3 /net/core/dev.c | |
parent | ba98898eb3fc07ee54566fcc3626354a44355acb (diff) | |
download | linux-fsl-qoriq-7004bf252c53da18f6b55103e0c92f777f846806.tar.xz |
net: add tx_packets/tx_bytes/tx_dropped counters in struct netdev_queue
offsetof(struct net_device, features)=0x44
offsetof(struct net_device, stats.tx_packets)=0x54
offsetof(struct net_device, stats.tx_bytes)=0x5c
offsetof(struct net_device, stats.tx_dropped)=0x6c
Network drivers that touch dev->stats.tx_packets/stats.tx_bytes in their
tx path can slow down SMP operations, since they dirty a cache line
that should stay shared (dev->features is needed in rx and tx paths)
We could move away stats field in net_device but it wont help that much.
(Two cache lines dirtied in tx path, we can do one only)
Better solution is to add tx_packets/tx_bytes/tx_dropped in struct
netdev_queue because this structure is already touched in tx path and
counters updates will then be free (no increase in size)
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
-rw-r--r-- | net/core/dev.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 14dd725..6d3630d 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4943,13 +4943,30 @@ void netdev_run_todo(void) * the internal statistics structure is used. */ const struct net_device_stats *dev_get_stats(struct net_device *dev) - { +{ const struct net_device_ops *ops = dev->netdev_ops; if (ops->ndo_get_stats) return ops->ndo_get_stats(dev); - else - return &dev->stats; + else { + unsigned long tx_bytes = 0, tx_packets = 0, tx_dropped = 0; + struct net_device_stats *stats = &dev->stats; + unsigned int i; + struct netdev_queue *txq; + + for (i = 0; i < dev->num_tx_queues; i++) { + txq = netdev_get_tx_queue(dev, i); + tx_bytes += txq->tx_bytes; + tx_packets += txq->tx_packets; + tx_dropped += txq->tx_dropped; + } + if (tx_bytes || tx_packets || tx_dropped) { + stats->tx_bytes = tx_bytes; + stats->tx_packets = tx_packets; + stats->tx_dropped = tx_dropped; + } + return stats; + } } EXPORT_SYMBOL(dev_get_stats); |