From d92c0da71a35dfddccca7bfa932829504311359e Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Mon, 6 Oct 2014 17:14:36 +0200 Subject: IB/srp: Add multichannel support 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 Reviewed-by: Sagi Grimberg Signed-off-by: Christoph Hellwig --- Documentation/ABI/stable/sysfs-driver-ib_srp | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) (limited to 'Documentation/ABI/stable') diff --git a/Documentation/ABI/stable/sysfs-driver-ib_srp b/Documentation/ABI/stable/sysfs-driver-ib_srp index b9688de8455b..7049a2b50359 100644 --- a/Documentation/ABI/stable/sysfs-driver-ib_srp +++ b/Documentation/ABI/stable/sysfs-driver-ib_srp @@ -55,12 +55,12 @@ Description: Interface for making ib_srp connect to a new target. only safe with partial memory descriptor list support enabled (allow_ext_sg=1). * comp_vector, a number in the range 0..n-1 specifying the - MSI-X completion vector. Some HCA's allocate multiple (n) - MSI-X vectors per HCA port. If the IRQ affinity masks of - these interrupts have been configured such that each MSI-X - interrupt is handled by a different CPU then the comp_vector - parameter can be used to spread the SRP completion workload - over multiple CPU's. + MSI-X completion vector of the first RDMA channel. Some + HCA's allocate multiple (n) MSI-X vectors per HCA port. If + the IRQ affinity masks of these interrupts have been + configured such that each MSI-X interrupt is handled by a + different CPU then the comp_vector parameter can be used to + spread the SRP completion workload over multiple CPU's. * tl_retry_count, a number in the range 2..7 specifying the IB RC retry count. * queue_size, the maximum number of commands that the @@ -88,6 +88,13 @@ Description: Whether ib_srp is allowed to include a partial memory descriptor list in an SRP_CMD when communicating with an SRP target. +What: /sys/class/scsi_host/host/ch_count +Date: April 1, 2015 +KernelVersion: 3.19 +Contact: linux-rdma@vger.kernel.org +Description: Number of RDMA channels used for communication with the SRP + target. + What: /sys/class/scsi_host/host/cmd_sg_entries Date: May 19, 2011 KernelVersion: 2.6.39 @@ -95,6 +102,12 @@ Contact: linux-rdma@vger.kernel.org Description: Maximum number of data buffer descriptors that may be sent to the target in a single SRP_CMD request. +What: /sys/class/scsi_host/host/comp_vector +Date: September 2, 2013 +KernelVersion: 3.11 +Contact: linux-rdma@vger.kernel.org +Description: Completion vector used for the first RDMA channel. + What: /sys/class/scsi_host/host/dgid Date: June 17, 2006 KernelVersion: 2.6.17 -- cgit v1.2.3