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Commit 4b5e5f41 authored by Bart Van Assche's avatar Bart Van Assche Committed by Roland Dreier
Browse files

IB/srp: Make HCA completion vector configurable 



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: default avatarBart Van Assche <bvanassche@acm.org>
Acked-by: default avatarDavid Dillow <dillowda@ornl.gov>
Signed-off-by: default avatarRoland Dreier <roland@purestorage.com>
parent 96fc248a

Documentation/ABI/stable/sysfs-driver-ib_srp

+7 −0
Original line number Diff line number Diff line
@@ -54,6 +54,13 @@ Description: Interface for making ib_srp connect to a new target. 
		  ib_srp. Specifying a value that exceeds cmd_sg_entries is

		  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.



What:		/sys/class/infiniband_srp/srp-<hca>-<port_number>/ibdev

Date:		January 2, 2006

drivers/infiniband/ulp/srp/ib_srp.c

+24 −2
Original line number Diff line number Diff line
@@ -231,14 +231,16 @@ static int srp_create_target_ib(struct srp_target_port *target) 
		return -ENOMEM;



	recv_cq = ib_create_cq(target->srp_host->srp_dev->dev,

			       srp_recv_completion, NULL, target, SRP_RQ_SIZE, 0);

			       srp_recv_completion, NULL, target, SRP_RQ_SIZE,

			       target->comp_vector);

	if (IS_ERR(recv_cq)) {

		ret = PTR_ERR(recv_cq);

		goto err;

	}



	send_cq = ib_create_cq(target->srp_host->srp_dev->dev,

			       srp_send_completion, NULL, target, SRP_SQ_SIZE, 0);

			       srp_send_completion, NULL, target, SRP_SQ_SIZE,

			       target->comp_vector);

	if (IS_ERR(send_cq)) {

		ret = PTR_ERR(send_cq);

		goto err_recv_cq;
@@ -1898,6 +1900,14 @@ static ssize_t show_local_ib_device(struct device *dev, 
	return sprintf(buf, "%s\n", target->srp_host->srp_dev->dev->name);

}



static ssize_t show_comp_vector(struct device *dev,

				struct device_attribute *attr, char *buf)

{

	struct srp_target_port *target = host_to_target(class_to_shost(dev));



	return sprintf(buf, "%d\n", target->comp_vector);

}



static ssize_t show_cmd_sg_entries(struct device *dev,

				   struct device_attribute *attr, char *buf)

{
@@ -1924,6 +1934,7 @@ static DEVICE_ATTR(req_lim, S_IRUGO, show_req_lim, NULL); 
static DEVICE_ATTR(zero_req_lim,    S_IRUGO, show_zero_req_lim,	   NULL);

static DEVICE_ATTR(local_ib_port,   S_IRUGO, show_local_ib_port,   NULL);

static DEVICE_ATTR(local_ib_device, S_IRUGO, show_local_ib_device, NULL);

static DEVICE_ATTR(comp_vector,     S_IRUGO, show_comp_vector,     NULL);

static DEVICE_ATTR(cmd_sg_entries,  S_IRUGO, show_cmd_sg_entries,  NULL);

static DEVICE_ATTR(allow_ext_sg,    S_IRUGO, show_allow_ext_sg,    NULL);
@@ -1938,6 +1949,7 @@ static struct device_attribute *srp_host_attrs[] = { 
	&dev_attr_zero_req_lim,

	&dev_attr_local_ib_port,

	&dev_attr_local_ib_device,

	&dev_attr_comp_vector,

	&dev_attr_cmd_sg_entries,

	&dev_attr_allow_ext_sg,

	NULL
@@ -2061,6 +2073,7 @@ enum { 
	SRP_OPT_CMD_SG_ENTRIES	= 1 << 9,

	SRP_OPT_ALLOW_EXT_SG	= 1 << 10,

	SRP_OPT_SG_TABLESIZE	= 1 << 11,

	SRP_OPT_COMP_VECTOR	= 1 << 12,

	SRP_OPT_ALL		= (SRP_OPT_ID_EXT	|

				   SRP_OPT_IOC_GUID	|

				   SRP_OPT_DGID		|
@@ -2081,6 +2094,7 @@ static const match_table_t srp_opt_tokens = { 
	{ SRP_OPT_CMD_SG_ENTRIES,	"cmd_sg_entries=%u"	},

	{ SRP_OPT_ALLOW_EXT_SG,		"allow_ext_sg=%u"	},

	{ SRP_OPT_SG_TABLESIZE,		"sg_tablesize=%u"	},

	{ SRP_OPT_COMP_VECTOR,		"comp_vector=%u"	},

	{ SRP_OPT_ERR,			NULL 			}

};
@@ -2236,6 +2250,14 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target) 
			target->sg_tablesize = token;

			break;



		case SRP_OPT_COMP_VECTOR:

			if (match_int(args, &token) || token < 0) {

				pr_warn("bad comp_vector parameter '%s'\n", p);

				goto out;

			}

			target->comp_vector = token;

			break;



		default:

			pr_warn("unknown parameter or missing value '%s' in target creation request\n",

				p);

drivers/infiniband/ulp/srp/ib_srp.h

+1 −0
Original line number Diff line number Diff line
@@ -156,6 +156,7 @@ struct srp_target_port { 
	char			target_name[32];

	unsigned int		scsi_id;

	unsigned int		sg_tablesize;

	int			comp_vector;



	struct ib_sa_path_rec	path;

	__be16			orig_dgid[8];