Improve performance by using multiple RDMA/RC channels per SCSI
host for communication with an SRP target. About the
implementation:
- Introduce a loop over all channels in the code that uses
target->ch.
- Set the SRP_MULTICHAN_MULTI flag during login for the creation
of the second and subsequent channels.
- RDMA completion vectors are chosen such that RDMA completion
interrupts are handled by the CPU socket that submitted the I/O
request. As one can see in this patch it has been assumed if a
system contains n CPU sockets and m RDMA completion vectors
have been assigned to an RDMA HCA that IRQ affinity has been
configured such that completion vectors [i*m/n..(i+1)*m/n) are
bound to CPU socket i with 0 <= i < n.
- Modify srp_free_ch_ib() and srp_free_req_data() such that it
becomes safe to invoke these functions after the corresponding
allocation function failed.
- Add a ch_count sysfs attribute per target port.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Certain storage configurations, e.g. a sufficiently large array of
hard disks in a RAID configuration, need a queue depth above 64 to
achieve optimal performance. Hence make the queue depth configurable.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Tested-by: Jack Wang <xjtuwjp@gmail.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
On an initiator system with multiple IB ports it is not yet possible
to figure out what the originating port of an SRP connection is. Hence
make the source GID available in sysfs.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Allow the InfiniBand RC retry count to be configured by the user as an
option in the target login string. Reducing this retry count allows to
reduce the path failover time.
Signed-off-by: Vu Pham <vu@mellanox.com>
[ bvanassche: Rewrote patch description / changed default retry count ]
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Several InfiniBand HCAs allow configuring the completion vector per
CQ. This allows spreading the workload created by IB completion
interrupts over multiple MSI-X vectors and hence over multiple CPU
cores. In other words, configuring the completion vector properly not
only allows reducing latency on an initiator connected to multiple
SRP targets but also allows improving throughput.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Document the sysfs attributes of the SRP initiator (ib_srp) according
to the rules specified in Documentation/ABI/README.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
