[PATCH v4] drm/amdgpu: add new trace event for page table update v3
Christian König
christian.koenig at amd.com
Wed Aug 19 13:04:33 UTC 2020
Am 19.08.20 um 14:37 schrieb Shashank Sharma:
> On 19/08/20 6:03 pm, Christian König wrote:
>> Am 19.08.20 um 14:19 schrieb Shashank Sharma:
>>> On 19/08/20 5:38 pm, Christian König wrote:
>>>> Am 19.08.20 um 13:52 schrieb Shashank Sharma:
>>>>> On 13/08/20 1:28 pm, Christian König wrote:
>>>>>> Am 13.08.20 um 05:04 schrieb Shashank Sharma:
>>>>>>> This patch adds a new trace event to track the PTE update
>>>>>>> events. This specific event will provide information like:
>>>>>>> - start and end of virtual memory mapping
>>>>>>> - HW engine flags for the map
>>>>>>> - physical address for mapping
>>>>>>>
>>>>>>> This will be particularly useful for memory profiling tools
>>>>>>> (like RMV) which are monitoring the page table update events.
>>>>>>>
>>>>>>> V2: Added physical address lookup logic in trace point
>>>>>>> V3: switch to use __dynamic_array
>>>>>>> added nptes int the TPprint arguments list
>>>>>>> added page size in the arg list
>>>>>>> V4: Addressed Christian's review comments
>>>>>>> add start/end instead of seg
>>>>>>> use incr instead of page_sz to be accurate
>>>>>>>
>>>>>>> Cc: Christian König <christian.koenig at amd.com>
>>>>>>> Cc: Alex Deucher <alexander.deucher at amd.com>
>>>>>>> Signed-off-by: Christian König <christian.koenig at amd.com>
>>>>>>> Signed-off-by: Shashank Sharma <shashank.sharma at amd.com>
>>>>>>> ---
>>>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h | 37 +++++++++++++++++++++++
>>>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 9 ++++--
>>>>>>> 2 files changed, 44 insertions(+), 2 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
>>>>>>> index 63e734a125fb..df12cf8466c2 100644
>>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
>>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
>>>>>>> @@ -321,6 +321,43 @@ DEFINE_EVENT(amdgpu_vm_mapping, amdgpu_vm_bo_cs,
>>>>>>> TP_ARGS(mapping)
>>>>>>> );
>>>>>>>
>>>>>>> +TRACE_EVENT(amdgpu_vm_update_ptes,
>>>>>>> + TP_PROTO(struct amdgpu_vm_update_params *p,
>>>>>>> + uint64_t start, uint64_t end,
>>>>>>> + unsigned int nptes, uint64_t dst,
>>>>>>> + uint64_t incr, uint64_t flags),
>>>>>>> + TP_ARGS(p, start, end, nptes, dst, incr, flags),
>>>>>>> + TP_STRUCT__entry(
>>>>>>> + __field(u64, start)
>>>>>>> + __field(u64, end)
>>>>>>> + __field(u64, flags)
>>>>>>> + __field(unsigned int, nptes)
>>>>>>> + __field(u64, incr)
>>>>>>> + __dynamic_array(u64, dst, nptes)
>>>>>> As discussed with the trace subsystem maintainer we need to add the pid
>>>>>> and probably the VM context ID we use here to identify the updated VM.
>>>>>>
>>>>>> Christian.
>>>>> I printed both vm->task_info.pid Vs current->pid for testing, and I can see different values coming out of .
>>>>>
>>>>> gnome-shell-2114 [011] 41.812894: amdgpu_vm_update_ptes: start:0x0800102e80 end:0x0800102e82, flags:0x80, incr:4096, pid=2128 vmid=0 cpid=2114
>>>>>
>>>>> pid is vm->task_info.pid=2128 whereas cpid=2114 is current.pid.
>>>>>
>>>>> Which is the one we want to send with the event ?
>>>> That is vm->task_info.pid, since this is the PID which is using the VM
>>>> for command submission.
>>> got it.
>>>>> Trace event by default seems to be adding the process name and id at the header of the event (gnome-shell-2114), which is same as current.pid
>>>>>
>>>>>
>>>>> Also, is it ok to extract vmid from job->vmid ?
>>>> Only in trace_amdgpu_vm_grab_id(), in all other cases it's probably not
>>>> assigned yet.
>>> Ok, let me check how can we get vmid from this context we are sending the event from. Or maybe I we should keep V5 with pid only, and later send a separate patch to add vmid ?
>> I'm not sure how you want to get a VMID in the first place. We
>> dynamically assign VMIDs during command submission.
>>
>> See the amdgpu_vm_grab_id trace point.
> Actually I was adding vmid to address this last comment on V4:
>> and probably the VM context ID we use here to identify the updated VM.
> I assumed you meant the vmid by this, is that not so ?
Ah! No that's something completely different :)
The VMID is a 4bit hardware identifier used for TLB optimization.
The VM context ID is an unique 64bit number, we usually use
vm->immediate.fence_context for this.
Regards,
Christian.
>
>
> Regards
>
> Shashank
>
>> Christian.
>>
>>> - Shashank
>>>
>>>> Christian.
>>>>
>>>>> Regards
>>>>>
>>>>> Shashank
>>>>>
>>>>>>> + ),
>>>>>>> +
>>>>>>> + TP_fast_assign(
>>>>>>> + unsigned int i;
>>>>>>> +
>>>>>>> + __entry->start = start;
>>>>>>> + __entry->end = end;
>>>>>>> + __entry->flags = flags;
>>>>>>> + __entry->incr = incr;
>>>>>>> + __entry->nptes = nptes;
>>>>>>> + for (i = 0; i < nptes; ++i) {
>>>>>>> + u64 addr = p->pages_addr ? amdgpu_vm_map_gart(
>>>>>>> + p->pages_addr, dst) : dst;
>>>>>>> +
>>>>>>> + ((u64 *)__get_dynamic_array(dst))[i] = addr;
>>>>>>> + dst += incr;
>>>>>>> + }
>>>>>>> + ),
>>>>>>> + TP_printk("start:0x%010llx end:0x%010llx, flags:0x%llx, incr:%llu,"
>>>>>>> + " dst:\n%s", __entry->start, __entry->end, __entry->flags,
>>>>>>> + __entry->incr, __print_array(
>>>>>>> + __get_dynamic_array(dst), __entry->nptes, 8))
>>>>>>> +);
>>>>>>> +
>>>>>>> TRACE_EVENT(amdgpu_vm_set_ptes,
>>>>>>> TP_PROTO(uint64_t pe, uint64_t addr, unsigned count,
>>>>>>> uint32_t incr, uint64_t flags, bool direct),
>>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>>> index 71e005cf2952..b5dbb5e8bc61 100644
>>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>>> @@ -1513,17 +1513,22 @@ static int amdgpu_vm_update_ptes(struct amdgpu_vm_update_params *params,
>>>>>>> do {
>>>>>>> uint64_t upd_end = min(entry_end, frag_end);
>>>>>>> unsigned nptes = (upd_end - frag_start) >> shift;
>>>>>>> + uint64_t upd_flags = flags | AMDGPU_PTE_FRAG(frag);
>>>>>>>
>>>>>>> /* This can happen when we set higher level PDs to
>>>>>>> * silent to stop fault floods.
>>>>>>> */
>>>>>>> nptes = max(nptes, 1u);
>>>>>>> +
>>>>>>> + trace_amdgpu_vm_update_ptes(params, frag_start, upd_end,
>>>>>>> + nptes, dst, incr,
>>>>>>> + upd_flags);
>>>>>>> amdgpu_vm_update_flags(params, pt, cursor.level,
>>>>>>> pe_start, dst, nptes, incr,
>>>>>>> - flags | AMDGPU_PTE_FRAG(frag));
>>>>>>> + upd_flags);
>>>>>>>
>>>>>>> pe_start += nptes * 8;
>>>>>>> - dst += (uint64_t)nptes * AMDGPU_GPU_PAGE_SIZE << shift;
>>>>>>> + dst += nptes * incr;
>>>>>>>
>>>>>>> frag_start = upd_end;
>>>>>>> if (frag_start >= frag_end) {
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