On Tue, Apr 27, 2021 at 4:32 AM Daniel Vetter daniel@ffwll.ch wrote:
On Fri, Apr 23, 2021 at 05:31:11PM -0500, Jason Ekstrand wrote:
This reverts commit 88be76cdafc7 ("drm/i915: Allow userspace to specify ringsize on construction"). This API was originally added for OpenCL but the compute-runtime PR has sat open for a year without action so we can still pull it out if we want. I argue we should drop it for three reasons:
If the compute-runtime PR has sat open for a year, this clearly isn't that important.
It's a very leaky API. Ring size is an implementation detail of the current execlist scheduler and really only makes sense there. It can't apply to the older ring-buffer scheduler on pre-execlist hardware because that's shared across all contexts and it won't apply to the GuC scheduler that's in the pipeline.
Having userspace set a ring size in bytes is a bad solution to the problem of having too small a ring. There is no way that userspace has the information to know how to properly set the ring size so it's just going to detect the feature and always set it to the maximum of 512K. This is what the compute-runtime PR does. The scheduler in i915, on the other hand, does have the information to make an informed choice. It could detect if the ring size is a problem and grow it itself. Or, if that's too hard, we could just increase the default size from 16K to 32K or even 64K instead of relying on userspace to do it.
Let's drop this API for now and, if someone decides they really care about solving this problem, they can do it properly.
Signed-off-by: Jason Ekstrand jason@jlekstrand.net
Two things:
- I'm assuming you have an igt change to make sure we get EINVAL for both set and getparam now? Just to make sure.
I've written up some quick tests. I'll send them out in the next version of the IGT series or as a separate series if that one gets reviewed without comment (unlikely).
- intel_context->ring is either a ring pointer when CONTEXT_ALLOC_BIT is set in ce->flags, or the size of the ring stored in the pointer if not. I'm seriously hoping you get rid of this complexity with your proto-context series, and also delete __intel_context_ring_size() in the end. That function has no business existing imo.
I hadn't done that yet, no. But I typed up a patch today which I'll send out with the next version of this series which does this.
--Jason
If not, please make sure that's the case.
Aside from these patch looks good.
Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch
drivers/gpu/drm/i915/Makefile | 1 - drivers/gpu/drm/i915/gem/i915_gem_context.c | 85 +------------------ drivers/gpu/drm/i915/gt/intel_context_param.c | 63 -------------- drivers/gpu/drm/i915/gt/intel_context_param.h | 3 - include/uapi/drm/i915_drm.h | 20 +---- 5 files changed, 4 insertions(+), 168 deletions(-) delete mode 100644 drivers/gpu/drm/i915/gt/intel_context_param.c
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile index d0d936d9137bc..afa22338fa343 100644 --- a/drivers/gpu/drm/i915/Makefile +++ b/drivers/gpu/drm/i915/Makefile @@ -88,7 +88,6 @@ gt-y += \ gt/gen8_ppgtt.o \ gt/intel_breadcrumbs.o \ gt/intel_context.o \
gt/intel_context_param.o \ gt/intel_context_sseu.o \ gt/intel_engine_cs.o \ gt/intel_engine_heartbeat.o \diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index fd8ee52e17a47..e52b85b8f923d 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -1335,63 +1335,6 @@ static int set_ppgtt(struct drm_i915_file_private *file_priv, return err; }
-static int __apply_ringsize(struct intel_context *ce, void *sz) -{
return intel_context_set_ring_size(ce, (unsigned long)sz);-}
-static int set_ringsize(struct i915_gem_context *ctx,
struct drm_i915_gem_context_param *args)-{
if (!HAS_LOGICAL_RING_CONTEXTS(ctx->i915))return -ENODEV;if (args->size)return -EINVAL;if (!IS_ALIGNED(args->value, I915_GTT_PAGE_SIZE))return -EINVAL;if (args->value < I915_GTT_PAGE_SIZE)return -EINVAL;if (args->value > 128 * I915_GTT_PAGE_SIZE)return -EINVAL;return context_apply_all(ctx,__apply_ringsize,__intel_context_ring_size(args->value));-}
-static int __get_ringsize(struct intel_context *ce, void *arg) -{
long sz;sz = intel_context_get_ring_size(ce);GEM_BUG_ON(sz > INT_MAX);return sz; /* stop on first engine */-}
-static int get_ringsize(struct i915_gem_context *ctx,
struct drm_i915_gem_context_param *args)-{
int sz;if (!HAS_LOGICAL_RING_CONTEXTS(ctx->i915))return -ENODEV;if (args->size)return -EINVAL;sz = context_apply_all(ctx, __get_ringsize, NULL);if (sz < 0)return sz;args->value = sz;return 0;-}
int i915_gem_user_to_context_sseu(struct intel_gt *gt, const struct drm_i915_gem_context_param_sseu *user, @@ -2037,11 +1980,8 @@ static int ctx_setparam(struct drm_i915_file_private *fpriv, ret = set_persistence(ctx, args); break;
case I915_CONTEXT_PARAM_RINGSIZE:ret = set_ringsize(ctx, args);break;case I915_CONTEXT_PARAM_BAN_PERIOD:
case I915_CONTEXT_PARAM_RINGSIZE: default: ret = -EINVAL; break;@@ -2069,18 +2009,6 @@ static int create_setparam(struct i915_user_extension __user *ext, void *data) return ctx_setparam(arg->fpriv, arg->ctx, &local.param); }
-static int copy_ring_size(struct intel_context *dst,
struct intel_context *src)-{
long sz;sz = intel_context_get_ring_size(src);if (sz < 0)return sz;return intel_context_set_ring_size(dst, sz);-}
static int clone_engines(struct i915_gem_context *dst, struct i915_gem_context *src) { @@ -2125,12 +2053,6 @@ static int clone_engines(struct i915_gem_context *dst, }
intel_context_set_gem(clone->engines[n], dst);
/* Copy across the preferred ringsize */if (copy_ring_size(clone->engines[n], e->engines[n])) {__free_engines(clone, n + 1);goto err_unlock;} } clone->num_engines = n; i915_sw_fence_complete(&e->fence);@@ -2490,11 +2412,8 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data, args->value = i915_gem_context_is_persistent(ctx); break;
case I915_CONTEXT_PARAM_RINGSIZE:ret = get_ringsize(ctx, args);break;case I915_CONTEXT_PARAM_BAN_PERIOD:
case I915_CONTEXT_PARAM_RINGSIZE: default: ret = -EINVAL; break;diff --git a/drivers/gpu/drm/i915/gt/intel_context_param.c b/drivers/gpu/drm/i915/gt/intel_context_param.c deleted file mode 100644 index 65dcd090245d6..0000000000000 --- a/drivers/gpu/drm/i915/gt/intel_context_param.c +++ /dev/null @@ -1,63 +0,0 @@ -// SPDX-License-Identifier: MIT -/*
- Copyright © 2019 Intel Corporation
- */
-#include "i915_active.h" -#include "intel_context.h" -#include "intel_context_param.h" -#include "intel_ring.h"
-int intel_context_set_ring_size(struct intel_context *ce, long sz) -{
int err;if (intel_context_lock_pinned(ce))return -EINTR;err = i915_active_wait(&ce->active);if (err < 0)goto unlock;if (intel_context_is_pinned(ce)) {err = -EBUSY; /* In active use, come back later! */goto unlock;}if (test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {struct intel_ring *ring;/* Replace the existing ringbuffer */ring = intel_engine_create_ring(ce->engine, sz);if (IS_ERR(ring)) {err = PTR_ERR(ring);goto unlock;}intel_ring_put(ce->ring);ce->ring = ring;/* Context image will be updated on next pin */} else {ce->ring = __intel_context_ring_size(sz);}-unlock:
intel_context_unlock_pinned(ce);return err;-}
-long intel_context_get_ring_size(struct intel_context *ce) -{
long sz = (unsigned long)READ_ONCE(ce->ring);if (test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {if (intel_context_lock_pinned(ce))return -EINTR;sz = ce->ring->size;intel_context_unlock_pinned(ce);}return sz;-} diff --git a/drivers/gpu/drm/i915/gt/intel_context_param.h b/drivers/gpu/drm/i915/gt/intel_context_param.h index 3ecacc675f414..dffedd983693d 100644 --- a/drivers/gpu/drm/i915/gt/intel_context_param.h +++ b/drivers/gpu/drm/i915/gt/intel_context_param.h @@ -10,9 +10,6 @@
#include "intel_context.h"
-int intel_context_set_ring_size(struct intel_context *ce, long sz); -long intel_context_get_ring_size(struct intel_context *ce);
static inline int intel_context_set_watchdog_us(struct intel_context *ce, u64 timeout_us) { diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index 6a34243a7646a..6eefbc6dec01f 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -1721,24 +1721,8 @@ struct drm_i915_gem_context_param { */ #define I915_CONTEXT_PARAM_PERSISTENCE 0xb
-/*
- I915_CONTEXT_PARAM_RINGSIZE:
- Sets the size of the CS ringbuffer to use for logical ring contexts. This
- applies a limit of how many batches can be queued to HW before the caller
- is blocked due to lack of space for more commands.
- Only reliably possible to be set prior to first use, i.e. during
- construction. At any later point, the current execution must be flushed as
- the ring can only be changed while the context is idle. Note, the ringsize
- can be specified as a constructor property, see
- I915_CONTEXT_CREATE_EXT_SETPARAM, but can also be set later if required.
- Only applies to the current set of engine and lost when those engines
- are replaced by a new mapping (see I915_CONTEXT_PARAM_ENGINES).
- Must be between 4 - 512 KiB, in intervals of page size [4 KiB].
- Default is 16 KiB.
+/* This API has been removed. On the off chance someone somewhere has
*/
- attempted to use it, never re-use this context param number.
#define I915_CONTEXT_PARAM_RINGSIZE 0xc /* Must be kept compact -- no holes and well documented */ -- 2.31.1
dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
-- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch