IB/qib: Optimize CQ callbacks
The current workqueue implemention has the following performance
deficiencies on QDR HCAs:
- The CQ call backs tend to run on the CPUs processing the
receive queues
- The single thread queue isn't optimal for multiple HCAs
This patch adds a dedicated per HCA bound thread to process CQ callbacks.
Reviewed-by: Ramkrishna Vepa <ramkrishna.vepa@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/hw/qib/qib.h b/drivers/infiniband/hw/qib/qib.h
index 2ee82e6..3a78b92c 100644
--- a/drivers/infiniband/hw/qib/qib.h
+++ b/drivers/infiniband/hw/qib/qib.h
@@ -1,7 +1,7 @@
#ifndef _QIB_KERNEL_H
#define _QIB_KERNEL_H
/*
- * Copyright (c) 2012 Intel Corporation. All rights reserved.
+ * Copyright (c) 2012, 2013 Intel Corporation. All rights reserved.
* Copyright (c) 2006 - 2012 QLogic Corporation. All rights reserved.
* Copyright (c) 2003, 2004, 2005, 2006 PathScale, Inc. All rights reserved.
*
@@ -51,6 +51,7 @@
#include <linux/completion.h>
#include <linux/kref.h>
#include <linux/sched.h>
+#include <linux/kthread.h>
#include "qib_common.h"
#include "qib_verbs.h"
@@ -1090,6 +1091,8 @@
u16 psxmitwait_check_rate;
/* high volume overflow errors defered to tasklet */
struct tasklet_struct error_tasklet;
+ /* per device cq worker */
+ struct kthread_worker *worker;
int assigned_node_id; /* NUMA node closest to HCA */
};
diff --git a/drivers/infiniband/hw/qib/qib_cq.c b/drivers/infiniband/hw/qib/qib_cq.c
index 5246aa4..ab4e11c 100644
--- a/drivers/infiniband/hw/qib/qib_cq.c
+++ b/drivers/infiniband/hw/qib/qib_cq.c
@@ -1,4 +1,5 @@
/*
+ * Copyright (c) 2013 Intel Corporation. All rights reserved.
* Copyright (c) 2006, 2007, 2008, 2010 QLogic Corporation. All rights reserved.
* Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
*
@@ -34,8 +35,10 @@
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
+#include <linux/kthread.h>
#include "qib_verbs.h"
+#include "qib.h"
/**
* qib_cq_enter - add a new entry to the completion queue
@@ -102,13 +105,18 @@
if (cq->notify == IB_CQ_NEXT_COMP ||
(cq->notify == IB_CQ_SOLICITED &&
(solicited || entry->status != IB_WC_SUCCESS))) {
- cq->notify = IB_CQ_NONE;
- cq->triggered++;
+ struct kthread_worker *worker;
/*
* This will cause send_complete() to be called in
* another thread.
*/
- queue_work(qib_cq_wq, &cq->comptask);
+ smp_rmb();
+ worker = cq->dd->worker;
+ if (likely(worker)) {
+ cq->notify = IB_CQ_NONE;
+ cq->triggered++;
+ queue_kthread_work(worker, &cq->comptask);
+ }
}
spin_unlock_irqrestore(&cq->lock, flags);
@@ -163,7 +171,7 @@
return npolled;
}
-static void send_complete(struct work_struct *work)
+static void send_complete(struct kthread_work *work)
{
struct qib_cq *cq = container_of(work, struct qib_cq, comptask);
@@ -287,11 +295,12 @@
* The number of entries should be >= the number requested or return
* an error.
*/
+ cq->dd = dd_from_dev(dev);
cq->ibcq.cqe = entries;
cq->notify = IB_CQ_NONE;
cq->triggered = 0;
spin_lock_init(&cq->lock);
- INIT_WORK(&cq->comptask, send_complete);
+ init_kthread_work(&cq->comptask, send_complete);
wc->head = 0;
wc->tail = 0;
cq->queue = wc;
@@ -323,7 +332,7 @@
struct qib_ibdev *dev = to_idev(ibcq->device);
struct qib_cq *cq = to_icq(ibcq);
- flush_work(&cq->comptask);
+ flush_kthread_work(&cq->comptask);
spin_lock(&dev->n_cqs_lock);
dev->n_cqs_allocated--;
spin_unlock(&dev->n_cqs_lock);
@@ -483,3 +492,49 @@
bail:
return ret;
}
+
+int qib_cq_init(struct qib_devdata *dd)
+{
+ int ret = 0;
+ int cpu;
+ struct task_struct *task;
+
+ if (dd->worker)
+ return 0;
+ dd->worker = kzalloc(sizeof(*dd->worker), GFP_KERNEL);
+ if (!dd->worker)
+ return -ENOMEM;
+ init_kthread_worker(dd->worker);
+ task = kthread_create_on_node(
+ kthread_worker_fn,
+ dd->worker,
+ dd->assigned_node_id,
+ "qib_cq%d", dd->unit);
+ if (IS_ERR(task))
+ goto task_fail;
+ cpu = cpumask_first(cpumask_of_node(dd->assigned_node_id));
+ kthread_bind(task, cpu);
+ wake_up_process(task);
+out:
+ return ret;
+task_fail:
+ ret = PTR_ERR(task);
+ kfree(dd->worker);
+ dd->worker = NULL;
+ goto out;
+}
+
+void qib_cq_exit(struct qib_devdata *dd)
+{
+ struct kthread_worker *worker;
+
+ worker = dd->worker;
+ if (!worker)
+ return;
+ /* blocks future queuing from send_complete() */
+ dd->worker = NULL;
+ smp_wmb();
+ flush_kthread_worker(worker);
+ kthread_stop(worker->task);
+ kfree(worker);
+}
diff --git a/drivers/infiniband/hw/qib/qib_init.c b/drivers/infiniband/hw/qib/qib_init.c
index e02217b..ff36903 100644
--- a/drivers/infiniband/hw/qib/qib_init.c
+++ b/drivers/infiniband/hw/qib/qib_init.c
@@ -97,8 +97,6 @@
module_param_named(wc_pat, qib_wc_pat, uint, S_IRUGO);
MODULE_PARM_DESC(wc_pat, "enable write-combining via PAT mechanism");
-struct workqueue_struct *qib_cq_wq;
-
static void verify_interrupt(unsigned long);
static struct idr qib_unit_table;
@@ -445,6 +443,7 @@
dd->intrchk_timer.function = verify_interrupt;
dd->intrchk_timer.data = (unsigned long) dd;
+ ret = qib_cq_init(dd);
done:
return ret;
}
@@ -1215,12 +1214,6 @@
if (ret)
goto bail;
- qib_cq_wq = create_singlethread_workqueue("qib_cq");
- if (!qib_cq_wq) {
- ret = -ENOMEM;
- goto bail_dev;
- }
-
/*
* These must be called before the driver is registered with
* the PCI subsystem.
@@ -1233,7 +1226,7 @@
ret = pci_register_driver(&qib_driver);
if (ret < 0) {
pr_err("Unable to register driver: error %d\n", -ret);
- goto bail_unit;
+ goto bail_dev;
}
/* not fatal if it doesn't work */
@@ -1241,13 +1234,11 @@
pr_err("Unable to register ipathfs\n");
goto bail; /* all OK */
-bail_unit:
+bail_dev:
#ifdef CONFIG_INFINIBAND_QIB_DCA
dca_unregister_notify(&dca_notifier);
#endif
idr_destroy(&qib_unit_table);
- destroy_workqueue(qib_cq_wq);
-bail_dev:
qib_dev_cleanup();
bail:
return ret;
@@ -1273,8 +1264,6 @@
#endif
pci_unregister_driver(&qib_driver);
- destroy_workqueue(qib_cq_wq);
-
qib_cpulist_count = 0;
kfree(qib_cpulist);
@@ -1365,6 +1354,7 @@
}
kfree(tmp);
kfree(dd->boardname);
+ qib_cq_exit(dd);
}
/*
diff --git a/drivers/infiniband/hw/qib/qib_verbs.h b/drivers/infiniband/hw/qib/qib_verbs.h
index aff8b2c..86c2cb3 100644
--- a/drivers/infiniband/hw/qib/qib_verbs.h
+++ b/drivers/infiniband/hw/qib/qib_verbs.h
@@ -41,6 +41,7 @@
#include <linux/interrupt.h>
#include <linux/kref.h>
#include <linux/workqueue.h>
+#include <linux/kthread.h>
#include <linux/completion.h>
#include <rdma/ib_pack.h>
#include <rdma/ib_user_verbs.h>
@@ -267,7 +268,8 @@
*/
struct qib_cq {
struct ib_cq ibcq;
- struct work_struct comptask;
+ struct kthread_work comptask;
+ struct qib_devdata *dd;
spinlock_t lock; /* protect changes in this struct */
u8 notify;
u8 triggered;
@@ -832,8 +834,6 @@
!(qp->s_flags & QIB_S_ANY_WAIT_SEND));
}
-extern struct workqueue_struct *qib_cq_wq;
-
/*
* This must be called with s_lock held.
*/
@@ -972,6 +972,10 @@
int qib_destroy_srq(struct ib_srq *ibsrq);
+int qib_cq_init(struct qib_devdata *dd);
+
+void qib_cq_exit(struct qib_devdata *dd);
+
void qib_cq_enter(struct qib_cq *cq, struct ib_wc *entry, int sig);
int qib_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry);
