On Thu, May 16, 2024 at 11:33:54AM GMT, Umesh Nerlige Ramappa wrote:
On Wed, May 15, 2024 at 02:42:56PM -0700, Lucas De Marchi wrote:
gt->info.engine_mask used to indicate the available engines, but that
is not always true anymore: some engines are reserved to kernel and some
may be exposed as a single engine (e.g. with ccs_mode).
Runtime changes only happen when no clients exist, so it's safe to cache
the list of engines in the gt and update that when it's needed. This
will help implementing per client engine utilization so this (mostly
constant) information doesn't need to be re-calculated on every query.
Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
Just a few questions below, otherwise this looks good as is:
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@xxxxxxxxx>
---
drivers/gpu/drm/xe/xe_gt.c | 23 +++++++++++++++++++++++
drivers/gpu/drm/xe/xe_gt.h | 13 +++++++++++++
drivers/gpu/drm/xe/xe_gt_ccs_mode.c | 1 +
drivers/gpu/drm/xe/xe_gt_types.h | 21 ++++++++++++++++++++-
4 files changed, 57 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
index e69a03ddd255..5194a3d38e76 100644
--- a/drivers/gpu/drm/xe/xe_gt.c
+++ b/drivers/gpu/drm/xe/xe_gt.c
@@ -560,9 +560,32 @@ int xe_gt_init(struct xe_gt *gt)
if (err)
return err;
+ xe_gt_record_user_engines(gt);
+
return drmm_add_action_or_reset(>_to_xe(gt)->drm, gt_fini, gt);
}
+void xe_gt_record_user_engines(struct xe_gt *gt)
+{
+ struct xe_hw_engine *hwe;
+ enum xe_hw_engine_id id;
+
+ gt->user_engines.mask = 0;
+ memset(gt->user_engines.instances_per_class, 0,
+ sizeof(gt->user_engines.instances_per_class));
+
+ for_each_hw_engine(hwe, gt, id) {
+ if (xe_hw_engine_is_reserved(hwe))
+ continue;
+
+ gt->user_engines.mask |= BIT_ULL(id);
+ gt->user_engines.instances_per_class[hwe->class]++;
+ }
+
+ xe_gt_assert(gt, (gt->user_engines.mask | gt->info.engine_mask)
+ == gt->info.engine_mask);
I am not seeing a place where user_engines.mask is not a subset of
info.engine_mask in the driver, so the above check will always be
true.
that's why it's an assert. user_engines.mask should always be a
subset of info.engine_mask, otherwise something went terribly wrong.
Did you mean to do and & instead of | above? That might make sense
since then you are making sure that the user_engines are a subset of
engine_mask.
no, what I'm trying to assert is that user_engines.mask never has an
engine that is not present in info.engine_mask. Example:
engine_mask == 0b01
user_engines.mask == 0b11
That should never happen and it should fail the assert.
I decided to add the assert because I'm not deriving the
user_engines.mask directly from the mask, but indirectly. Early on probe
we setup the mask and create the hw_engine instances and we are
calculating the user_engines.mask from there. I just wanted to make sure
we don't screw up something in the middle that causes issues.
+}
+
static int do_gt_reset(struct xe_gt *gt)
{
int err;
diff --git a/drivers/gpu/drm/xe/xe_gt.h b/drivers/gpu/drm/xe/xe_gt.h
index 8474c50b1b30..ad3fd31e0a41 100644
--- a/drivers/gpu/drm/xe/xe_gt.h
+++ b/drivers/gpu/drm/xe/xe_gt.h
@@ -38,6 +38,19 @@ int xe_gt_init_hwconfig(struct xe_gt *gt);
int xe_gt_init_early(struct xe_gt *gt);
int xe_gt_init(struct xe_gt *gt);
int xe_gt_record_default_lrcs(struct xe_gt *gt);
+
+/**
+ * @xe_gt_record_user_engines - save data related to engines available to
+ * usersapce
+ * @gt: GT structure
+ *
+ * Walk the available HW engines from gt->info.engine_mask and calculate data
+ * related to those engines that may be used by userspace. To be used whenever
+ * available engines change in runtime (e.g. with ccs_mode) or during
After the driver loads, do we expect ccs_mode to change dynamically
based on some criteria OR is it a one time configuration at driver
load?
If former, can you provide an example where ccs_mode would change
dynamically, just curious.
it can be set via sysfs, but it blocks changing it if there are clients.
For with display, it's easier to check by loading the driver with
enable_display=0. Trying that on a DG2:
# modprobe xe enable_display=0
# exec 3<> /dev/dri/card1
# tail -n4 /proc/self/fdinfo/3
drm-cycles-bcs: 0
drm-total-cycles-bcs: 37728138157
drm-cycles-ccs: 0
drm-total-cycles-ccs: 37728138157
#
# exec 3<&-
# echo 2 > /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/0000:02:01.0/0000:03:00.0/tile0/gt0/ccs_mode
# exec 3<> /dev/dri/card1
# tail -n4 /proc/self/fdinfo/3
drm-total-cycles-bcs: 38260910526
drm-cycles-ccs: 0
drm-total-cycles-ccs: 38260910526
drm-engine-capacity-ccs: 2
thanks
Lucas De Marchi
Regards,
Umesh
+ * initialization
+ */
+void xe_gt_record_user_engines(struct xe_gt *gt);
+
void xe_gt_suspend_prepare(struct xe_gt *gt);
int xe_gt_suspend(struct xe_gt *gt);
int xe_gt_resume(struct xe_gt *gt);
diff --git a/drivers/gpu/drm/xe/xe_gt_ccs_mode.c b/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
index a34c9a24dafc..c36218f4f6c8 100644
--- a/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
+++ b/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
@@ -134,6 +134,7 @@ ccs_mode_store(struct device *kdev, struct device_attribute *attr,
if (gt->ccs_mode != num_engines) {
xe_gt_info(gt, "Setting compute mode to %d\n", num_engines);
gt->ccs_mode = num_engines;
+ xe_gt_record_user_engines(gt);
xe_gt_reset_async(gt);
}
diff --git a/drivers/gpu/drm/xe/xe_gt_types.h b/drivers/gpu/drm/xe/xe_gt_types.h
index 5a114fc9dde7..aaf2951749a6 100644
--- a/drivers/gpu/drm/xe/xe_gt_types.h
+++ b/drivers/gpu/drm/xe/xe_gt_types.h
@@ -112,7 +112,11 @@ struct xe_gt {
enum xe_gt_type type;
/** @info.reference_clock: clock frequency */
u32 reference_clock;
- /** @info.engine_mask: mask of engines present on GT */
+ /**
+ * @info.engine_mask: mask of engines present on GT. Some of
+ * them may be reserved in runtime and not available for user.
+ * See @user_engines.mask
+ */
u64 engine_mask;
/** @info.gmdid: raw GMD_ID value from hardware */
u32 gmdid;
@@ -365,6 +369,21 @@ struct xe_gt {
/** @wa_active.oob: bitmap with active OOB workaroudns */
unsigned long *oob;
} wa_active;
+
+ /** @user_engines: engines present in GT and available to userspace */
+ struct {
+ /**
+ * @mask: like @info->engine_mask, but take in consideration
+ * only engines available to userspace
+ */
+ u64 mask;
+
+ /**
+ * @instances_per_class: aggregate per class the number of
+ * engines available to userspace
+ */
+ u8 instances_per_class[XE_ENGINE_CLASS_MAX];
+ } user_engines;
};
#endif
--
2.43.0
