On 10/04/2023 16:04, Bas Nieuwenhuizen wrote:
On Mon, Apr 10, 2023 at 4:01 PM Shashank Sharma <shashank.sharma@xxxxxxx> wrote:
On 10/04/2023 15:46, Bas Nieuwenhuizen wrote:
On Mon, Apr 10, 2023 at 3:40 PM Sharma, Shashank
<Shashank.Sharma@xxxxxxx> wrote:
[AMD Official Use Only - General]
Hello Bas,
This is not the correct interpretation of the code, the USERQ_IOCTL has both the OPs (create and destroy), but th euser has to exclusively call it.
Please see the sample test program in the existing libDRM series (userq_test.c, it specifically calls amdgpu_free_userq, which does the destroy_OP
for the IOCTL.
In the presence of crashes the kernel should always be able to clean
this up no? Otherwise there is a resource leak?
The crash handling is the same as any of the existing GPU resource which
are allocated and freed with IOCTL_OPs.
Most of those are handled in the when the DRM fd gets closed (i.e.
when the process exits):
- buffers through drm_gem_release()
- mappings in amdgpu_vm_fini
- contexts in amdgpu_ctx_mgr_fini
etc.
Why would we do things differently for userspace queues? It doesn't
look complicated looking at the above patch (which does seem to work).
As the code is in initial stage, I have not given much thoughts about
handling resource leak due to app crash, but this seems like a good
suggestion.
I am taking a note and will try to accommodate this in an upcoming
version of the series.
- Shashank
To be honest a crash handling can be very elaborated and complex one,
and hence only can be done at the driver unload IMO, which doesn't help
at that stage,
coz anyways driver will re-allocate the resources on next load.
- Shashank
- Shashank
-----Original Message-----
From: Bas Nieuwenhuizen <bas@xxxxxxxxxxxxxxxxxxx>
Sent: 10 April 2023 11:26
To: Sharma, Shashank <Shashank.Sharma@xxxxxxx>
Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx; Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Kuehling, Felix <Felix.Kuehling@xxxxxxx>; Koenig, Christian <Christian.Koenig@xxxxxxx>; Yadav, Arvind <Arvind.Yadav@xxxxxxx>
Subject: Re: [PATCH v3 0/9] AMDGPU Usermode queues
Hi Shashank,
I think I found the issue: I wasn't destroying the user queue in my program and the kernel doesn't clean up any remaining user queues in the postclose hook. I think we need something like
https://github.com/BNieuwenhuizen/linux/commit/e90c8d1185da7353c12837973ceddf55ccc85d29
?
While running things multiple times now works, I still have problems doing multiple submissions from the same queue. Looking forward to the updated test/sample
Thanks,
Bas
On Mon, Apr 10, 2023 at 9:32 AM Sharma, Shashank <Shashank.Sharma@xxxxxxx> wrote:
[AMD Official Use Only - General]
Hello Bas,
Thanks for trying this out.
This could be due to the doorbell as you mentioned, Usermode queue uses doorbell manager internally.
This week, we are planning to publis the latest libDRM sample code which uses a doorbell object (instead of the doorbell hack IOCTL), adapting to that should fix your problem in my opinion.
We have tested this full stack (libDRM test + Usermode queue + doorbell manager) for 500+ consecutive runs, and it worked well for us.
You can use this integrated kernel stack (1+2) from my gitlab to build
your kernel:
https://gitlab.freedesktop.org/contactshashanksharma/userq-amdgpu/-/tr
ee/integrated-db-and-uq-v3 Please stay tuned for updated libDRM
changes with doorbell objects.
Regards
Shashank
-----Original Message-----
From: Bas Nieuwenhuizen <bas@xxxxxxxxxxxxxxxxxxx>
Sent: 10 April 2023 02:37
To: Sharma, Shashank <Shashank.Sharma@xxxxxxx>
Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx; Deucher, Alexander
<Alexander.Deucher@xxxxxxx>; Kuehling, Felix <Felix.Kuehling@xxxxxxx>;
Koenig, Christian <Christian.Koenig@xxxxxxx>
Subject: Re: [PATCH v3 0/9] AMDGPU Usermode queues
Hi Shashank,
I tried writing a program to experiment with usermode queues and I found some weird behavior: The first run of the program works as expected, while subsequent runs don't seem to do anything (and I allocate everything in GTT, so it should be zero initialized consistently). Is this a known issue?
The linked libdrm code for the uapi still does a doorbell ioctl so it could very well be that I do the doorbell wrong (especially since the ioctl implementation was never shared AFAICT?), but it seems like the kernel submissions (i.e. write wptr in dwords to the wptr va and to the doorbell). Is it possible to update the test in libdrm?
Code: https://gitlab.freedesktop.org/bnieuwenhuizen/usermode-queue
Thanks,
Bas
On Wed, Mar 29, 2023 at 6:05 PM Shashank Sharma <shashank.sharma@xxxxxxx> wrote:
This patch series introduces AMDGPU usermode queues for gfx workloads.
Usermode queues is a method of GPU workload submission into the
graphics hardware without any interaction with kernel/DRM schedulers.
In this method, a userspace graphics application can create its own
workqueue and submit it directly in the GPU HW.
The general idea of how this is supposed to work:
- The application creates the following GPU objetcs:
- A queue object to hold the workload packets.
- A read pointer object.
- A write pointer object.
- A doorbell page.
- The application picks a 32-bit offset in the doorbell page for this queue.
- The application uses the usermode_queue_create IOCTL introduced in
this patch, by passing the the GPU addresses of these objects (read
ptr, write ptr, queue base address and 32-bit doorbell offset from
the doorbell page)
- The kernel creates the queue and maps it in the HW.
- The application can start submitting the data in the queue as soon as
the kernel IOCTL returns.
- After filling the workload data in the queue, the app must write the
number of dwords added in the queue into the doorbell offset, and the
GPU will start fetching the data.
libDRM changes for this series and a sample DRM test program can be
found in the MESA merge request here:
https://gitlab.freedesktop.org/mesa/drm/-/merge_requests/287
This patch series depends on the doorbell-manager changes, which are
being reviewed here:
https://patchwork.freedesktop.org/series/115802/
Alex Deucher (1):
drm/amdgpu: UAPI for user queue management
Arvind Yadav (2):
drm/amdgpu: add new parameters in v11_struct
drm/amdgpu: map wptr BO into GART
Shashank Sharma (6):
drm/amdgpu: add usermode queue base code
drm/amdgpu: add new IOCTL for usermode queue
drm/amdgpu: create GFX-gen11 MQD for userqueue
drm/amdgpu: create context space for usermode queue
drm/amdgpu: map usermode queue into MES
drm/amdgpu: generate doorbell index for userqueue
drivers/gpu/drm/amd/amdgpu/Makefile | 3 +
drivers/gpu/drm/amd/amdgpu/amdgpu.h | 10 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 2 +
drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 6 +
drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c | 298
++++++++++++++++++ .../drm/amd/amdgpu/amdgpu_userqueue_gfx_v11.c |
++++++++++++++++++ 230 ++++++++++++++
.../gpu/drm/amd/include/amdgpu_userqueue.h | 66 ++++
drivers/gpu/drm/amd/include/v11_structs.h | 16 +-
include/uapi/drm/amdgpu_drm.h | 55 ++++
9 files changed, 677 insertions(+), 9 deletions(-) create mode
100644 drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
create mode 100644
drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue_gfx_v11.c
create mode 100644 drivers/gpu/drm/amd/include/amdgpu_userqueue.h
--
2.40.0
