Am 27.04.2017 um 12:26 schrieb zhoucm1:
On 2017年04月27日 17:51, Christian König wrote:
Patch #1, #2, #4 and #6 are Reviewed-by: Christian König
<[email protected]>.
Patch #3:
+ /* Select the first entry VMID */
+ idle = list_first_entry(&id_mgr->ids_lru, struct amdgpu_vm_id,
list);
+ list_del_init(&idle->list);
+ vm->reserved_vmid[vmhub] = idle;
+ mutex_unlock(&id_mgr->lock);
I think we should wait for the VMID to be completely idle before we
can use it, but that possible also go into the handling in patch #5.
Yes.
Patch #5:
+ if ((amdgpu_vm_had_gpu_reset(adev, id)) ||
+ (atomic64_read(&id->owner) != vm->client_id) ||
+ (job->vm_pd_addr != id->pd_gpu_addr) ||
+ (updates && (!flushed || updates->context !=
flushed->context ||
+ fence_is_later(updates, flushed)))) {
You also need this check here as well:
if (!id->last_flush ||
(id->last_flush->context != fence_context &&
!fence_is_signaled(id->last_flush)))
added.
+ tmp = amdgpu_sync_get_fence(&id->active);
+ if (tmp) {
+ r = amdgpu_sync_fence(adev, sync, tmp);
+ fence_put(tmp);
+ return r;
+ }
That won't work correctly.
The first problem is that amdgpu_sync_get_fence() removes the fence
from the active fences. So a another command submission from a
different context won't wait for all the necessary fences. I think
using amdgpu_sync_peek_fence() instead should work here.
good catch.
The second problem is that a context could be starved when it needs a
VM flush while another context can still submit jobs without a flush.
I think you could work around that by setting id->pd_gpu_addr to an
invalid value when we hit this case. This way all other contexts
would need to do a VM flush as well.
I don't catch your opinion, when you object concurrent flush, isn't it
expected?
Imagine the following scenario:
Two contexts in use by the application.
Context 1 has a bunch of jobs to do, but needs a VM flush before
starting them.
So each job will just pick the first fence to wait for go to sleep again.
Context 2 has a bunch of jobs to do, but does NOT need a VM flush.
This will add more and more fences to the collection of active jobs for
this id.
The result is that Context 1 will never be able to submit any of it's
jobs because context 2 keeps the ID busy all the time.
Setting the pd_gpu_addr to some invalid value (or maybe the ID owner?)
should fix that. In this case context 2 needs to flush as well and so
context 1 will sooner or later get a chance as well.
Regards,
Christian.
+ id->pd_gpu_addr = job->vm_pd_addr;
+ id->current_gpu_reset_count =
atomic_read(&adev->gpu_reset_counter);
+ atomic64_set(&id->owner, vm->client_id);
+ job->vm_needs_flush = needs_flush;
If we need a flush id->last_flush needs to be set to NULL here as
well. E.g. do
fence_put(id->last_flush);
id->last_flush = NULL;
changed.
Regards,
David Zhou
Regards,
Christian.
Am 27.04.2017 um 07:00 schrieb Chunming Zhou:
The current kernel implementation, which grabs the idle VMID from
pool when emitting the job may:
The back-to-back submission from one process could use
different VMID.
The submission to different queues from single process could
use different VMID
It works well in most case but cannot work for the SQ thread trace
capture.
The VMID for the submission that set the {SQTT}_BASE, which refers
to the address of the trace buffer, is stored in shader engine.
If the profiling application have to use different VMIDs to submit
IBs in its life cycle:
Some trace is not captured since it actually uses different
VMID to submit jobs.
Some part of captured trace may come from different application
since they are accidentally uses the owner’s VMID to submit jobs.
V2:
1. address Christian's comments:
a. drop context flags for tag process, instead, add vm ioctl.
b. change order of patches.
c. sync waiting only when vm flush needs.
2. address Alex's comments;
bump module version
V3:
address Jerry and Christian's comments.
and only reserve gfxhub vmid
v4:
address Jerry and Christian's comments.
fix some race condistions.
Chunming Zhou (6):
drm/amdgpu: add vm ioctl
drm/amdgpu: add reserved vmid field in vm struct v2
drm/amdgpu: reserve/unreserve vmid by vm ioctl v4
drm/amdgpu: add limitation for dedicated vm number v4
drm/amdgpu: implement grab reserved vmid V3
drm/amdgpu: bump module verion for reserved vmid
drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 3 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 1 +
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 152
++++++++++++++++++++++++++++++--
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 6 ++
include/uapi/drm/amdgpu_drm.h | 22 +++++
5 files changed, 178 insertions(+), 6 deletions(-)
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