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Commit bfee5e32 authored by Vennila Megavannan's avatar Vennila Megavannan Committed by Doug Ledford
Browse files

IB/rdmavt, staging/rdma/hfi1: use qps to dynamically scale timeout value 



A busy_jiffies variable is maintained and updated when rc qps are
created and deleted. busy_jiffies is a scaled value of the number
of rc qps in the device. busy_jiffies is incremented every rc qp
scaling interval. busy_jiffies is added to the rc timeout
in add_retry_timer and mod_retry_timer. The rc qp scaling interval
is selected based on extensive performance evaluation of targeted
workloads.

Reviewed-by: default avatarDennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: default avatarMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: default avatarVennila Megavannan <vennila.megavannan@intel.com>
Signed-off-by: default avatarJubin John <jubin.john@intel.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent 773d0451

drivers/infiniband/sw/rdmavt/qp.c

+17 −0
Original line number Diff line number Diff line
@@ -685,6 +685,19 @@ struct ib_qp *rvt_create_qp(struct ib_pd *ibpd, 
	}



	rdi->n_qps_allocated++;

	/*

	 * Maintain a busy_jiffies variable that will be added to the timeout

	 * period in mod_retry_timer and add_retry_timer. This busy jiffies

	 * is scaled by the number of rc qps created for the device to reduce

	 * the number of timeouts occurring when there is a large number of

	 * qps. busy_jiffies is incremented every rc qp scaling interval.

	 * The scaling interval is selected based on extensive performance

	 * evaluation of targeted workloads.

	 */

	if (init_attr->qp_type == IB_QPT_RC) {

		rdi->n_rc_qps++;

		rdi->busy_jiffies = rdi->n_rc_qps / RC_QP_SCALING_INTERVAL;

	}

	spin_unlock(&rdi->n_qps_lock);



	if (qp->ip) {
@@ -1223,6 +1236,10 @@ int rvt_destroy_qp(struct ib_qp *ibqp) 


	spin_lock(&rdi->n_qps_lock);

	rdi->n_qps_allocated--;

	if (qp->ibqp.qp_type == IB_QPT_RC) {

		rdi->n_rc_qps--;

		rdi->busy_jiffies = rdi->n_rc_qps / RC_QP_SCALING_INTERVAL;

	}

	spin_unlock(&rdi->n_qps_lock);



	if (qp->ip)

drivers/staging/rdma/hfi1/rc.c

+10 −2
Original line number Diff line number Diff line
@@ -68,9 +68,13 @@ 
 */

static inline void hfi1_add_retry_timer(struct rvt_qp *qp)

{

	struct ib_qp *ibqp = &qp->ibqp;

	struct rvt_dev_info *rdi = ib_to_rvt(ibqp->device);



	qp->s_flags |= RVT_S_TIMER;

	/* 4.096 usec. * (1 << qp->timeout) */

	qp->s_timer.expires = jiffies + qp->timeout_jiffies;

	qp->s_timer.expires = jiffies + qp->timeout_jiffies +

			      rdi->busy_jiffies;

	add_timer(&qp->s_timer);

}
@@ -99,9 +103,13 @@ void hfi1_add_rnr_timer(struct rvt_qp *qp, u32 to) 
 */

static inline void hfi1_mod_retry_timer(struct rvt_qp *qp)

{

	struct ib_qp *ibqp = &qp->ibqp;

	struct rvt_dev_info *rdi = ib_to_rvt(ibqp->device);



	qp->s_flags |= RVT_S_TIMER;

	/* 4.096 usec. * (1 << qp->timeout) */

	mod_timer(&qp->s_timer, jiffies + qp->timeout_jiffies);

	mod_timer(&qp->s_timer, jiffies + qp->timeout_jiffies +

		  rdi->busy_jiffies);

}



/**

include/rdma/rdma_vt.h

+3 −1
Original line number Diff line number Diff line
@@ -318,7 +318,9 @@ struct rvt_dev_info { 
	/* QP */

	struct rvt_qp_ibdev *qp_dev;

	u32 n_qps_allocated;    /* number of QPs allocated for device */

	spinlock_t n_qps_lock; /* keep track of number of qps */

	u32 n_rc_qps;		/* number of RC QPs allocated for device */

	u32 busy_jiffies;	/* timeout scaling based on RC QP count */

	spinlock_t n_qps_lock;	/* protect qps, rc qps and busy jiffy counts */



	/* memory maps */

	struct list_head pending_mmaps;

include/rdma/rdmavt_qp.h

+2 −0
Original line number Diff line number Diff line
@@ -225,6 +225,8 @@ struct rvt_ack_entry { 
	};

};



#define	RC_QP_SCALING_INTERVAL	5



/*

 * Variables prefixed with s_ are for the requester (sender).

 * Variables prefixed with r_ are for the responder (receiver).