IB/hfi1: Change default number of user contexts

Change the default number of user contexts to the number of real
(non-HT) cpu cores in order to reduce the division of hfi1 hardware
contexts in the case of high core counts with hyper-threading enabled.

Reviewed-by: Dean Luick <[email protected]>
Reviewed-by: Dennis Dalessandro <[email protected]>
Reviewed-by: Mitko Haralanov <[email protected]>
Signed-off-by: Jubin John <[email protected]>
Signed-off-by: Doug Ledford <[email protected]>

Author: jubinjohn

drivers/staging/rdma/hfi1/affinity.c

@@ -53,20 +53,6 @@
 #include "sdma.h"
 #include "trace.h"
 
-struct cpu_mask_set {
-	struct cpumask mask;
-	struct cpumask used;
-	uint gen;
-};
-
-struct hfi1_affinity {
-	struct cpu_mask_set def_intr;
-	struct cpu_mask_set rcv_intr;
-	struct cpu_mask_set proc;
-	/* spin lock to protect affinity struct */
-	spinlock_t lock;
-};
-
 /* Name of IRQ types, indexed by enum irq_type */
 static const char * const irq_type_names[] = {
 	"SDMA",
@@ -82,6 +68,48 @@ static inline void init_cpu_mask_set(struct cpu_mask_set *set)
 	set->gen = 0;
 }
 
+/* Initialize non-HT cpu cores mask */
+int init_real_cpu_mask(struct hfi1_devdata *dd)
+{
+	struct hfi1_affinity *info;
+	int possible, curr_cpu, i, ht;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	cpumask_clear(&info->real_cpu_mask);
+
+	/* Start with cpu online mask as the real cpu mask */
+	cpumask_copy(&info->real_cpu_mask, cpu_online_mask);
+
+	/*
+	 * Remove HT cores from the real cpu mask.  Do this in two steps below.
+	 */
+	possible = cpumask_weight(&info->real_cpu_mask);
+	ht = cpumask_weight(topology_sibling_cpumask(
+					cpumask_first(&info->real_cpu_mask)));
+	/*
+	 * Step 1.  Skip over the first N HT siblings and use them as the
+	 * "real" cores.  Assumes that HT cores are not enumerated in
+	 * succession (except in the single core case).
+	 */
+	curr_cpu = cpumask_first(&info->real_cpu_mask);
+	for (i = 0; i < possible / ht; i++)
+		curr_cpu = cpumask_next(curr_cpu, &info->real_cpu_mask);
+	/*
+	 * Step 2.  Remove the remaining HT siblings.  Use cpumask_next() to
+	 * skip any gaps.
+	 */
+	for (; i < possible; i++) {
+		cpumask_clear_cpu(curr_cpu, &info->real_cpu_mask);
+		curr_cpu = cpumask_next(curr_cpu, &info->real_cpu_mask);
+	}
+
+	dd->affinity = info;
+	return 0;
+}
+
 /*
  * Interrupt affinity.
  *
@@ -93,20 +121,17 @@ static inline void init_cpu_mask_set(struct cpu_mask_set *set)
  * to the node relative 1 as necessary.
  *
  */
-int hfi1_dev_affinity_init(struct hfi1_devdata *dd)
+void hfi1_dev_affinity_init(struct hfi1_devdata *dd)
 {
 	int node = pcibus_to_node(dd->pcidev->bus);
-	struct hfi1_affinity *info;
+	struct hfi1_affinity *info = dd->affinity;
 	const struct cpumask *local_mask;
-	int curr_cpu, possible, i, ht;
+	int curr_cpu, possible, i;
 
 	if (node < 0)
 		node = numa_node_id();
 	dd->node = node;
 
-	info = kzalloc(sizeof(*info), GFP_KERNEL);
-	if (!info)
-		return -ENOMEM;
 	spin_lock_init(&info->lock);
 
 	init_cpu_mask_set(&info->def_intr);
@@ -116,30 +141,8 @@ int hfi1_dev_affinity_init(struct hfi1_devdata *dd)
 	local_mask = cpumask_of_node(dd->node);
 	if (cpumask_first(local_mask) >= nr_cpu_ids)
 		local_mask = topology_core_cpumask(0);
-	/* use local mask as default */
-	cpumask_copy(&info->def_intr.mask, local_mask);
-	/*
-	 * Remove HT cores from the default mask.  Do this in two steps below.
-	 */
-	possible = cpumask_weight(&info->def_intr.mask);
-	ht = cpumask_weight(topology_sibling_cpumask(
-					cpumask_first(&info->def_intr.mask)));
-	/*
-	 * Step 1.  Skip over the first N HT siblings and use them as the
-	 * "real" cores.  Assumes that HT cores are not enumerated in
-	 * succession (except in the single core case).
-	 */
-	curr_cpu = cpumask_first(&info->def_intr.mask);
-	for (i = 0; i < possible / ht; i++)
-		curr_cpu = cpumask_next(curr_cpu, &info->def_intr.mask);
-	/*
-	 * Step 2.  Remove the remaining HT siblings.  Use cpumask_next() to
-	 * skip any gaps.
-	 */
-	for (; i < possible; i++) {
-		cpumask_clear_cpu(curr_cpu, &info->def_intr.mask);
-		curr_cpu = cpumask_next(curr_cpu, &info->def_intr.mask);
-	}
+	/* Use the "real" cpu mask of this node as the default */
+	cpumask_and(&info->def_intr.mask, &info->real_cpu_mask, local_mask);
 
 	/*  fill in the receive list */
 	possible = cpumask_weight(&info->def_intr.mask);
@@ -167,8 +170,6 @@ int hfi1_dev_affinity_init(struct hfi1_devdata *dd)
 	}
 
 	cpumask_copy(&info->proc.mask, cpu_online_mask);
-	dd->affinity = info;
-	return 0;
 }
 
 void hfi1_dev_affinity_free(struct hfi1_devdata *dd)

drivers/staging/rdma/hfi1/affinity.h

@@ -64,10 +64,27 @@ enum affinity_flags {
 	AFF_IRQ_LOCAL
 };
 
+struct cpu_mask_set {
+	struct cpumask mask;
+	struct cpumask used;
+	uint gen;
+};
+
+struct hfi1_affinity {
+	struct cpu_mask_set def_intr;
+	struct cpu_mask_set rcv_intr;
+	struct cpu_mask_set proc;
+	struct cpumask real_cpu_mask;
+	/* spin lock to protect affinity struct */
+	spinlock_t lock;
+};
+
 struct hfi1_msix_entry;
 
+/* Initialize non-HT cpu cores mask */
+int init_real_cpu_mask(struct hfi1_devdata *);
 /* Initialize driver affinity data */
-int hfi1_dev_affinity_init(struct hfi1_devdata *);
+void hfi1_dev_affinity_init(struct hfi1_devdata *);
 /* Free driver affinity data */
 void hfi1_dev_affinity_free(struct hfi1_devdata *);
 /*

drivers/staging/rdma/hfi1/chip.c

@@ -12656,12 +12656,13 @@ static int set_up_context_variables(struct hfi1_devdata *dd)
 		num_kernel_contexts = dd->chip_send_contexts - num_vls - 1;
 	}
 	/*
-	 * User contexts: (to be fixed later)
-	 *	- default to 1 user context per CPU if num_user_contexts is
-	 *	  negative
+	 * User contexts:
+	 *	- default to 1 user context per real (non-HT) CPU core if
+	 *	  num_user_contexts is negative
 	 */
 	if (num_user_contexts < 0)
-		num_user_contexts = num_online_cpus();
+		num_user_contexts =
+			cpumask_weight(&dd->affinity->real_cpu_mask);
 
 	total_contexts = num_kernel_contexts + num_user_contexts;
 
@@ -14089,6 +14090,19 @@ struct hfi1_devdata *hfi1_init_dd(struct pci_dev *pdev,
 		 (dd->revision >> CCE_REVISION_SW_SHIFT)
 		    & CCE_REVISION_SW_MASK);
 
+	/*
+	 * The real cpu mask is part of the affinity struct but has to be
+	 * initialized earlier than the rest of the affinity struct because it
+	 * is needed to calculate the number of user contexts in
+	 * set_up_context_variables(). However, hfi1_dev_affinity_init(),
+	 * which initializes the rest of the affinity struct members,
+	 * depends on set_up_context_variables() for the number of kernel
+	 * contexts, so it cannot be called before set_up_context_variables().
+	 */
+	ret = init_real_cpu_mask(dd);
+	if (ret)
+		goto bail_cleanup;
+
 	ret = set_up_context_variables(dd);
 	if (ret)
 		goto bail_cleanup;
@@ -14102,9 +14116,7 @@ struct hfi1_devdata *hfi1_init_dd(struct pci_dev *pdev,
 	/* set up KDETH QP prefix in both RX and TX CSRs */
 	init_kdeth_qp(dd);
 
-	ret = hfi1_dev_affinity_init(dd);
-	if (ret)
-		goto bail_cleanup;
+	hfi1_dev_affinity_init(dd);
 
 	/* send contexts must be set up before receive contexts */
 	ret = init_send_contexts(dd);