Re: [RFC PATCH 00/10] Make XPS usable within ixgbe

Hi Alexander,

Thanks for this work!

Some general comments:

1) skb_tx_hash is called from a handful of drivers (bnx2x, ixgbe,
mlx4, and bonding).  Would it make sent to call xps_get_cpu from that
function (unfortunately the use of ndo_select_queue is likely
bypassing xps unnecessarily in these drivers).
2) Instead of (or maybe in addition to) allowing driver to program xps
maps, we could parameterize get_xps_cpu to optionally include a bit
map of acceptable queues.  This would be useful to define a
hierarchical queue selection (like first choose a set for QoS, then
amongst those chose one base on xps).

Tom

On Fri, Jun 29, 2012 at 5:16 PM, Alexander Duyck
[off-list ref] wrote:

The following patch series makes it so that the ixgbe driver can support
ATR even when the number of queues is less than the number of CPUs.  To do
this I have updated the kernel to support letting drivers set their own XPS
configuration.  To do this it was necessary to move the code out of the
sysfs specific code and into the dev specific regions.

I am still working out a few issues such as the fact that with routing I
only ever seem to be able to get the first queue that is mapped to the CPU
when XPS is enabled.

Also I am looking for input on if it is acceptable to only let the
set_channels/get_channels calls report/set the number of queues per traffic
class as I implemented the code this way to avoid any significant conflicts
between the DCB traffic classes code and these functions.

---

Alexander Duyck (10):
      ixgbe: Add support for set_channels ethtool operation
      ixgbe: Add support for displaying the number of Tx/Rx channels
      ixgbe: Update ixgbe driver to use __dev_pick_tx in ixgbe_select_queue
      ixgbe: Add function for setting XPS queue mapping
      ixgbe: Define FCoE and Flow director limits much sooner to allow for changes
      net: Add support for XPS without SYSFS being defined
      net: Rewrite netif_set_xps_queues to address several issues
      net: Rewrite netif_reset_xps_queue to allow for better code reuse
      net: Add functions netif_reset_xps_queue and netif_set_xps_queue
      net: Split core bits of dev_pick_tx into __dev_pick_tx


 drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c |  112 +++++++++
 drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c     |   10 -
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c    |   48 +++-
 include/linux/netdevice.h                        |   15 +
 net/Kconfig                                      |    2
 net/core/dev.c                                   |  283 ++++++++++++++++++++--
 net/core/net-sysfs.c                             |  160 ------------
 7 files changed, 428 insertions(+), 202 deletions(-)

--
Thanks,

Alex