linux_dsm_epyc7002/drivers/infiniband
Michael S. Tsirkin 839fcaba35 IPoIB: Connected mode experimental support
The following patch adds experimental support for IPoIB connected
mode, as defined by the draft from the IETF ipoib working group.  The
idea is to increase performance by increasing the MTU from the maximum
of 2K (theoretically 4K) supported by IPoIB on top of UD.  With this
code, I'm able to get 800MByte/sec or more with netperf without
options on a Mellanox 4x back-to-back DDR system.

Some notes on code:
1. SRQ is used for scalability to large cluster sizes
2. Only RC connections are used (UC does not support SRQ now)
3. Retry count is set to 0 since spec draft warns against retries
4. Each connection is used for data transfers in only 1 direction, so
   each connection is either active(TX) or passive (RX).  2 sides that
   want to communicate create 2 connections.
5. Each active (TX) connection has a separate CQ for send completions -
   this keeps the code simple without CQ resize and other tricks
6. To detect stale passive side connections (where the remote side is
   down), we keep an LRU list of passive connections (updated once per
   second per connection) and destroy a connection after it has been
   unused for several seconds. The LRU rule makes it possible to avoid
   scanning connections that have recently been active.

Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
2007-02-10 08:00:48 -08:00
..
core IB/core: Use ARRAY_SIZE macro for mandatory_table 2007-02-10 08:00:47 -08:00
hw IB/mthca: Use correct structure size in call to memset() 2007-02-10 08:00:47 -08:00
ulp IPoIB: Connected mode experimental support 2007-02-10 08:00:48 -08:00
Kconfig RDMA/amso1100: Add driver for Ammasso 1100 RNIC 2006-09-22 15:22:48 -07:00
Makefile RDMA/amso1100: Add driver for Ammasso 1100 RNIC 2006-09-22 15:22:48 -07:00