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2010-11-29xps: Add CONFIG_XPSTom Herbert
This patch adds XPS_CONFIG option to enable and disable XPS. This is done in the same manner as RPS_CONFIG. This is also fixes build failure in XPS code when SMP is not enabled. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-24xps: Transmit Packet SteeringTom Herbert
This patch implements transmit packet steering (XPS) for multiqueue devices. XPS selects a transmit queue during packet transmission based on configuration. This is done by mapping the CPU transmitting the packet to a queue. This is the transmit side analogue to RPS-- where RPS is selecting a CPU based on receive queue, XPS selects a queue based on the CPU (previously there was an XPS patch from Eric Dumazet, but that might more appropriately be called transmit completion steering). Each transmit queue can be associated with a number of CPUs which will use the queue to send packets. This is configured as a CPU mask on a per queue basis in: /sys/class/net/eth<n>/queues/tx-<n>/xps_cpus The mappings are stored per device in an inverted data structure that maps CPUs to queues. In the netdevice structure this is an array of num_possible_cpu structures where each structure holds and array of queue_indexes for queues which that CPU can use. The benefits of XPS are improved locality in the per queue data structures. Also, transmit completions are more likely to be done nearer to the sending thread, so this should promote locality back to the socket on free (e.g. UDP). The benefits of XPS are dependent on cache hierarchy, application load, and other factors. XPS would nominally be configured so that a queue would only be shared by CPUs which are sharing a cache, the degenerative configuration woud be that each CPU has it's own queue. Below are some benchmark results which show the potential benfit of this patch. The netperf test has 500 instances of netperf TCP_RR test with 1 byte req. and resp. bnx2x on 16 core AMD XPS (16 queues, 1 TX queue per CPU) 1234K at 100% CPU No XPS (16 queues) 996K at 100% CPU Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-28net: Allow changing number of RX queues after device allocationBen Hutchings
For RPS, we create a kobject for each RX queue based on the number of queues passed to alloc_netdev_mq(). However, drivers generally do not determine the numbers of hardware queues to use until much later, so this usually represents the maximum number the driver may use and not the actual number in use. For TX queues, drivers can update the actual number using netif_set_real_num_tx_queues(). Add a corresponding function for RX queues, netif_set_real_num_rx_queues(). Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-21net: Expose all network devices in a namespaces in sysfsEric W. Biederman
This reverts commit aaf8cdc34ddba08122f02217d9d684e2f9f5d575. Drivers like the ipw2100 call device_create_group when they are initialized and device_remove_group when they are shutdown. Moving them between namespaces deletes their sysfs groups early. In particular the following call chain results. netdev_unregister_kobject -> device_del -> kobject_del -> sysfs_remove_dir With sysfs_remove_dir recursively deleting all of it's subdirectories, and nothing adding them back. Ouch! Therefore we need to call something that ultimate calls sysfs_mv_dir as that sysfs function can move sysfs directories between namespaces without deleting their subdirectories or their contents. Allowing us to avoid placing extra boiler plate into every driver that does something interesting with sysfs. Currently the function that provides that capability is device_rename. That is the code works without nasty side effects as originally written. So remove the misguided fix for moving devices between namespaces. The bug in the kobject layer that inspired it has now been recognized and fixed. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-05-03netns: Fix device renaming for sysfsDaniel Lezcano
When a netdev is moved across namespaces with the 'dev_change_net_namespace' function, the 'device_rename' function is used to fixup kobject and refresh the sysfs tree. The device_rename function will call kobject_rename and this one will check if there is an object with the same name and this is the case because we are renaming the object with the same name. The use of 'device_rename' seems for me wrong because we usually don't rename it but just move it across namespaces. As we just want to do a mini "netdev_[un]register", IMO the functions 'netdev_[un]register_kobject' should be used instead, like an usual network device [un]registering. This patch replace device_rename by netdev_unregister_kobject, followed by netdev_register_kobject. The netdev_register_kobject will call device_initialize and will raise a warning indicating the device was already initialized. In order to fix that, I split the device initialization into a separate function and use it together with 'netdev_register_kobject' into register_netdevice. So we can safely call 'netdev_register_kobject' in 'dev_change_net_namespace'. This fix will allow to properly use the sysfs per namespace which is coming from -mm tree. Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Acked-by: Benjamin Thery <benjamin.thery@bull.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-24[NET]: Remove in-code externs for some functions from net/core/dev.cPavel Emelyanov
Inconsistent prototype and real type for functions may have worse consequences, than those for variables, so move them into a header. Since they are used privately in net/core, make this file reside in the same place. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>