[PATCH 03/14] drm/amdkfd: map multiple processes to HW scheduler

[Felix Kuehling]

Allow HWS to to execute multiple processes on the hardware
concurrently. The number of concurrent processes is limited by
the number of VMIDs allocated to the HWS.

A module parameter can be used for limiting this further or turn
it off altogether (mainly for debugging purposes).

Signed-off-by: Yong Zhao <yong.zhao at amd.com>
Signed-off-by: Jay Cornwall <Jay.Cornwall at amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_device.c         | 11 +++++++++
 drivers/gpu/drm/amd/amdkfd/kfd_module.c         |  5 +++++
 drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c | 30 +++++++++++++++++++++++--
 drivers/gpu/drm/amd/amdkfd/kfd_priv.h           |  9 ++++++++
 4 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device.c b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
index 4f05eac..a8fa33a 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
@@ -238,6 +238,17 @@ bool kgd2kfd_device_init(struct kfd_dev *kfd,
 	kfd->vm_info.vmid_num_kfd = kfd->vm_info.last_vmid_kfd
 			- kfd->vm_info.first_vmid_kfd + 1;
 
+	/* Verify module parameters regarding mapped process number*/
+	if ((hws_max_conc_proc < 0)
+			|| (hws_max_conc_proc > kfd->vm_info.vmid_num_kfd)) {
+		dev_err(kfd_device,
+			"hws_max_conc_proc %d must be between 0 and %d, use %d instead\n",
+			hws_max_conc_proc, kfd->vm_info.vmid_num_kfd,
+			kfd->vm_info.vmid_num_kfd);
+		kfd->max_proc_per_quantum = kfd->vm_info.vmid_num_kfd;
+	} else
+		kfd->max_proc_per_quantum = hws_max_conc_proc;
+
 	/* calculate max size of mqds needed for queues */
 	size = max_num_of_queues_per_device *
 			kfd->device_info->mqd_size_aligned;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_module.c b/drivers/gpu/drm/amd/amdkfd/kfd_module.c
index ee8adf6..4e060c8 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_module.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_module.c
@@ -50,6 +50,11 @@ module_param(sched_policy, int, 0444);
 MODULE_PARM_DESC(sched_policy,
 	"Scheduling policy (0 = HWS (Default), 1 = HWS without over-subscription, 2 = Non-HWS (Used for debugging only)");
 
+int hws_max_conc_proc = 8;
+module_param(hws_max_conc_proc, int, 0444);
+MODULE_PARM_DESC(hws_max_conc_proc,
+	"Max # processes HWS can execute concurrently when sched_policy=0 (0 = no concurrency, #VMIDs for KFD = Maximum(default))");
+
 int cwsr_enable = 1;
 module_param(cwsr_enable, int, 0444);
 MODULE_PARM_DESC(cwsr_enable, "CWSR enable (0 = Off, 1 = On (Default))");
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c
index 69c147a..0b7092e 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c
@@ -57,13 +57,24 @@ static void pm_calc_rlib_size(struct packet_manager *pm,
 {
 	unsigned int process_count, queue_count;
 	unsigned int map_queue_size;
+	unsigned int max_proc_per_quantum = 1;
+	struct kfd_dev *dev = pm->dqm->dev;
 
 	process_count = pm->dqm->processes_count;
 	queue_count = pm->dqm->queue_count;
 
-	/* check if there is over subscription*/
+	/* check if there is over subscription
+	 * Note: the arbitration between the number of VMIDs and
+	 * hws_max_conc_proc has been done in
+	 * kgd2kfd_device_init().
+	 */
 	*over_subscription = false;
-	if ((process_count > 1) || queue_count > get_queues_num(pm->dqm)) {
+
+	if (dev->max_proc_per_quantum > 1)
+		max_proc_per_quantum = dev->max_proc_per_quantum;
+
+	if ((process_count > max_proc_per_quantum) ||
+	    queue_count > get_queues_num(pm->dqm)) {
 		*over_subscription = true;
 		pr_debug("Over subscribed runlist\n");
 	}
@@ -116,10 +127,24 @@ static int pm_create_runlist(struct packet_manager *pm, uint32_t *buffer,
 			uint64_t ib, size_t ib_size_in_dwords, bool chain)
 {
 	struct pm4_mes_runlist *packet;
+	int concurrent_proc_cnt = 0;
+	struct kfd_dev *kfd = pm->dqm->dev;
 
 	if (WARN_ON(!ib))
 		return -EFAULT;
 
+	/* Determine the number of processes to map together to HW:
+	 * it can not exceed the number of VMIDs available to the
+	 * scheduler, and it is determined by the smaller of the number
+	 * of processes in the runlist and kfd module parameter
+	 * hws_max_conc_proc.
+	 * Note: the arbitration between the number of VMIDs and
+	 * hws_max_conc_proc has been done in
+	 * kgd2kfd_device_init().
+	 */
+	concurrent_proc_cnt = min(pm->dqm->processes_count,
+			kfd->max_proc_per_quantum);
+
 	packet = (struct pm4_mes_runlist *)buffer;
 
 	memset(buffer, 0, sizeof(struct pm4_mes_runlist));
@@ -130,6 +155,7 @@ static int pm_create_runlist(struct packet_manager *pm, uint32_t *buffer,
 	packet->bitfields4.chain = chain ? 1 : 0;
 	packet->bitfields4.offload_polling = 0;
 	packet->bitfields4.valid = 1;
+	packet->bitfields4.process_cnt = concurrent_proc_cnt;
 	packet->ordinal2 = lower_32_bits(ib);
 	packet->bitfields3.ib_base_hi = upper_32_bits(ib);
 
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index a668764..1edab21 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -88,6 +88,12 @@ extern int max_num_of_queues_per_device;
 /* Kernel module parameter to specify the scheduling policy */
 extern int sched_policy;
 
+/*
+ * Kernel module parameter to specify the maximum process
+ * number per HW scheduler
+ */
+extern int hws_max_conc_proc;
+
 extern int cwsr_enable;
 
 /*
@@ -214,6 +220,9 @@ struct kfd_dev {
 	/* Debug manager */
 	struct kfd_dbgmgr           *dbgmgr;
 
+	/* Maximum process number mapped to HW scheduler */
+	unsigned int max_proc_per_quantum;
+
 	/* CWSR */
 	bool cwsr_enabled;
 	const void *cwsr_isa;
-- 
2.7.4