[PATCH v2 3/7] drm/xe: Add debugfs knobs to control long running workload timeslicing

[Matthew Brost <matthew.brost@intel.com>]

Add debugfs knobs to control timeslicing for long-running workloads,
allowing quick tuning of values when running benchmarks.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
 drivers/gpu/drm/xe/xe_debugfs.c      | 74 ++++++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_device.c       |  1 +
 drivers/gpu/drm/xe/xe_device_types.h |  6 +++
 drivers/gpu/drm/xe/xe_vm.c           |  4 +-
 4 files changed, 83 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c
index 4fa423a82bea..38433c9af59f 100644
--- a/drivers/gpu/drm/xe/xe_debugfs.c
+++ b/drivers/gpu/drm/xe/xe_debugfs.c
@@ -328,6 +328,74 @@ static const struct file_operations atomic_svm_timeslice_ms_fops = {
 	.write = atomic_svm_timeslice_ms_set,
 };
 
+static ssize_t min_run_period_lr_ms_show(struct file *f, char __user *ubuf,
+					 size_t size, loff_t *pos)
+{
+	struct xe_device *xe = file_inode(f)->i_private;
+	char buf[32];
+	int len = 0;
+
+	len = scnprintf(buf, sizeof(buf), "%d\n", xe->min_run_period_lr_ms);
+
+	return simple_read_from_buffer(ubuf, size, pos, buf, len);
+}
+
+static ssize_t min_run_period_lr_ms_set(struct file *f, const char __user *ubuf,
+					size_t size, loff_t *pos)
+{
+	struct xe_device *xe = file_inode(f)->i_private;
+	u32 min_run_period_lr_ms;
+	ssize_t ret;
+
+	ret = kstrtouint_from_user(ubuf, size, 0, &min_run_period_lr_ms);
+	if (ret)
+		return ret;
+
+	xe->min_run_period_lr_ms = min_run_period_lr_ms;
+
+	return size;
+}
+
+static const struct file_operations min_run_period_lr_ms_fops = {
+	.owner = THIS_MODULE,
+	.read = min_run_period_lr_ms_show,
+	.write = min_run_period_lr_ms_set,
+};
+
+static ssize_t min_run_period_pf_ms_show(struct file *f, char __user *ubuf,
+					 size_t size, loff_t *pos)
+{
+	struct xe_device *xe = file_inode(f)->i_private;
+	char buf[32];
+	int len = 0;
+
+	len = scnprintf(buf, sizeof(buf), "%d\n", xe->min_run_period_pf_ms);
+
+	return simple_read_from_buffer(ubuf, size, pos, buf, len);
+}
+
+static ssize_t min_run_period_pf_ms_set(struct file *f, const char __user *ubuf,
+					size_t size, loff_t *pos)
+{
+	struct xe_device *xe = file_inode(f)->i_private;
+	u32 min_run_period_pf_ms;
+	ssize_t ret;
+
+	ret = kstrtouint_from_user(ubuf, size, 0, &min_run_period_pf_ms);
+	if (ret)
+		return ret;
+
+	xe->min_run_period_pf_ms = min_run_period_pf_ms;
+
+	return size;
+}
+
+static const struct file_operations min_run_period_pf_ms_fops = {
+	.owner = THIS_MODULE,
+	.read = min_run_period_pf_ms_show,
+	.write = min_run_period_pf_ms_set,
+};
+
 static ssize_t disable_late_binding_show(struct file *f, char __user *ubuf,
 					 size_t size, loff_t *pos)
 {
@@ -395,6 +463,12 @@ void xe_debugfs_register(struct xe_device *xe)
 	debugfs_create_file("atomic_svm_timeslice_ms", 0600, root, xe,
 			    &atomic_svm_timeslice_ms_fops);
 
+	debugfs_create_file("min_run_period_lr_ms", 0600, root, xe,
+			    &min_run_period_lr_ms_fops);
+
+	debugfs_create_file("min_run_period_pf_ms", 0600, root, xe,
+			    &min_run_period_pf_ms_fops);
+
 	debugfs_create_file("disable_late_binding", 0600, root, xe,
 			    &disable_late_binding_fops);
 
diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 339b9aef9499..9f84ce3db1f6 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -460,6 +460,7 @@ struct xe_device *xe_device_create(struct pci_dev *pdev,
 	xe->info.revid = pdev->revision;
 	xe->info.force_execlist = xe_modparam.force_execlist;
 	xe->atomic_svm_timeslice_ms = 5;
+	xe->min_run_period_lr_ms = 5;
 
 	err = xe_irq_init(xe);
 	if (err)
diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index b35ba29d4d35..7df0da592b50 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -615,6 +615,12 @@ struct xe_device {
 	/** @atomic_svm_timeslice_ms: Atomic SVM fault timeslice MS */
 	u32 atomic_svm_timeslice_ms;
 
+	/** @min_run_period_lr_ms: LR VM (preempt fence mode) timeslice */
+	u32 min_run_period_lr_ms;
+
+	/** @min_run_period_pf_ms: LR VM (page fault mode) timeslice */
+	u32 min_run_period_pf_ms;
+
 #ifdef TEST_VM_OPS_ERROR
 	/**
 	 * @vm_inject_error_position: inject errors at different places in VM
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 4648f8a458cf..a1363f675b51 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -1509,9 +1509,9 @@ struct xe_vm *xe_vm_create(struct xe_device *xe, u32 flags, struct xe_file *xef)
 
 	INIT_LIST_HEAD(&vm->preempt.exec_queues);
 	if (flags & XE_VM_FLAG_FAULT_MODE)
-		vm->preempt.min_run_period_ms = 0;
+		vm->preempt.min_run_period_ms = xe->min_run_period_pf_ms;
 	else
-		vm->preempt.min_run_period_ms = 5;
+		vm->preempt.min_run_period_ms = xe->min_run_period_lr_ms;
 
 	for_each_tile(tile, xe, id)
 		xe_range_fence_tree_init(&vm->rftree[id]);
-- 
2.34.1