I see about the access now, but did you even look at the patch?
I did look at the patch, but I haven't fully understood yet what you are trying to do here.
Because what the patch does isn't even exposed to common drm code, such as the preferred domain and visible VRAM placement, so it can't be in fdinfo right now.
Or do you even know what fdinfo contains? Because it contains nothing useful. It only has VRAM and GTT usage, which we already have in the INFO ioctl, so it has nothing that we need. We mainly need the eviction information and visible VRAM information now. Everything else is a bonus.
Well the main question is what are you trying to get from that information? The eviction list for example is completely meaningless to userspace, that stuff is only temporary and will be cleared on the next CS again.
What we could expose is the VRAM over-commit value, e.g. how much BOs which where supposed to be in VRAM are in GTT now. I think that's what you are looking for here, right?
Also, it's undesirable to open and parse a text file if we can just call an ioctl.
Well I see the reasoning for that, but I also see why other drivers do a lot of the stuff we have as IOCTL as separate files in sysfs, fdinfo or debugfs.
Especially repeating all the static information which were already available under sysfs in the INFO IOCTL was a design mistake as far as I can see. Just compare what AMDGPU and the KFD code is doing to what for example i915 is doing.
Same for things like debug information about a process. The fdinfo stuff can be queried from external tools (gdb, gputop, umr etc...) as well which makes that interface more preferred.
So do you want me to move it into amdgpu_vm.c? Because you could have just said: Let's move it into amdgpu_vm.c. :)
Thanks,
Marek
On Tue, Jan 3, 2023 at 3:33 AM Christian König <ckoenig.leichtzumerken@xxxxxxxxx> wrote:
Take a look at /proc/self/fdinfo/$fd.
The Intel guys made that vendor agnostic and are using it within their IGT gpu top tool.
Christian.
Am 02.01.23 um 18:57 schrieb Marek Olšák:
What are you talking about? Is fdinfo in sysfs? Userspace drivers can't access sysfs.
Marek
On Mon, Jan 2, 2023, 10:56 Christian König <ckoenig.leichtzumerken@xxxxxxxxx> wrote:
Well first of all don't mess with the VM internals outside of the VM code.
Then why would we want to expose this through the IOCTL interface? We already have this in the fdinfo.
Christian.
Am 30.12.22 um 23:07 schrieb Marek Olšák:
To give userspace a detailed view about its GPU memory usage and evictions.
This will help performance investigations.
Signed-off-by: Marek Olšák <marek.olsak@xxxxxxx>
The patch is attached.
Marek
