kernel_optimize_test/drivers/net
David Woodhouse e675f0cc9a ppp: Don't stop and restart queue on every TX packet
For every transmitted packet, ppp_start_xmit() will stop the netdev
queue and then, if appropriate, restart it. This causes the TX softirq
to run, entirely gratuitously.

This is "only" a waste of CPU time in the normal case, but it's actively
harmful when the PPP device is a TEQL slave — the wakeup will cause the
offending device to receive the next TX packet from the TEQL queue, when
it *should* have gone to the next slave in the list. We end up seeing
large bursts of packets on just *one* slave device, rather than using
the full available bandwidth over all slaves.

This patch fixes the problem by *not* unconditionally stopping the queue
in ppp_start_xmit(). It adds a return value from ppp_xmit_process()
which indicates whether the queue should be stopped or not.

It *doesn't* remove the call to netif_wake_queue() from
ppp_xmit_process(), because other code paths (especially from
ppp_output_wakeup()) need it there and it's messy to push it out to the
other callers to do it based on the return value. So we leave it in
place — it's a no-op in the case where the queue wasn't stopped, so it's
harmless in the TX path.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-03 17:31:38 -04:00
..
appletalk Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
arcnet Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
bonding Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-04-02 17:53:39 -07:00
caif Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-03-09 14:34:20 -08:00
can Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
cris Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
dsa
ethernet Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-04-02 17:53:39 -07:00
fddi
hamradio Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
hippi Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
hyperv net/hyperv: Fix the code handling tx busy 2012-03-19 17:27:06 -04:00
irda Disintegrate and delete asm/system.h 2012-03-28 15:58:21 -07:00
phy Generialize powerpc's irq_host as irq_domain 2012-03-21 10:27:19 -07:00
plip Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
ppp ppp: Don't stop and restart queue on every TX packet 2012-04-03 17:31:38 -04:00
slip Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
team
tokenring Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
usb net: usb: cdc_eem: fix mtu 2012-04-01 23:32:35 -04:00
vmxnet3 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-03-05 21:16:26 -05:00
wan Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
wimax wimax: i2400m-usb - use a private struct ethtool_ops 2012-03-27 22:30:09 -04:00
wireless Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-04-02 17:53:39 -07:00
xen-netback
dummy.c
eql.c eql: dont rely on HZ=100 2012-03-27 22:45:26 -04:00
ifb.c
Kconfig
LICENSE.SRC
loopback.c Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
macvlan.c
macvtap.c
Makefile
mdio.c ethtool, mdio, mii: Specify MDIO information fields in struct ethtool_cmd 2012-03-01 16:41:26 -05:00
mii.c ethtool, mdio, mii: Specify MDIO information fields in struct ethtool_cmd 2012-03-01 16:41:26 -05:00
netconsole.c
rionet.c rionet: fix page allocation order of rionet_active 2012-04-01 23:17:16 -04:00
sb1000.c
Space.c
sungem_phy.c
tun.c Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
veth.c
virtio_net.c virtio_net: do not rate limit counter increments 2012-03-28 04:40:45 -04:00
xen-netfront.c One tiny feature that accidentally got lost in the initial git pull: 2012-03-24 12:20:25 -07:00