[PATCH 5/6] drm/amdgpu: flip frag_ptes and update_pts
Christian König
deathsimple at vodafone.de
Tue Aug 9 12:52:51 UTC 2016
From: Christian König <christian.koenig at amd.com>
We can add the fragment params before we split the update for the page tables.
That should save a few CPU cycles for larger updates.
Signed-off-by: Christian König <christian.koenig at amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 166 ++++++++++++++++-----------------
1 file changed, 79 insertions(+), 87 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 6d90b2c..e6c030b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -701,83 +701,6 @@ error_free:
}
/**
- * amdgpu_vm_frag_ptes - add fragment information to PTEs
- *
- * @params: see amdgpu_pte_update_params definition
- * @pe_start: first PTE to handle
- * @pe_end: last PTE to handle
- * @addr: addr those PTEs should point to
- * @flags: hw mapping flags
- */
-static void amdgpu_vm_frag_ptes(struct amdgpu_pte_update_params *params,
- uint64_t pe_start, uint64_t pe_end,
- uint64_t addr, uint32_t flags)
-{
- /**
- * The MC L1 TLB supports variable sized pages, based on a fragment
- * field in the PTE. When this field is set to a non-zero value, page
- * granularity is increased from 4KB to (1 << (12 + frag)). The PTE
- * flags are considered valid for all PTEs within the fragment range
- * and corresponding mappings are assumed to be physically contiguous.
- *
- * The L1 TLB can store a single PTE for the whole fragment,
- * significantly increasing the space available for translation
- * caching. This leads to large improvements in throughput when the
- * TLB is under pressure.
- *
- * The L2 TLB distributes small and large fragments into two
- * asymmetric partitions. The large fragment cache is significantly
- * larger. Thus, we try to use large fragments wherever possible.
- * Userspace can support this by aligning virtual base address and
- * allocation size to the fragment size.
- */
-
- /* SI and newer are optimized for 64KB */
- uint64_t frag_flags = AMDGPU_PTE_FRAG(AMDGPU_LOG2_PAGES_PER_FRAG);
- uint64_t frag_align = 0x80;
-
- uint64_t frag_start = ALIGN(pe_start, frag_align);
- uint64_t frag_end = pe_end & ~(frag_align - 1);
-
- unsigned count;
-
- /* Abort early if there isn't anything to do */
- if (pe_start == pe_end)
- return;
-
- /* system pages are non continuously */
- if (params->src || params->pages_addr ||
- !(flags & AMDGPU_PTE_VALID) || (frag_start >= frag_end)) {
-
- count = (pe_end - pe_start) / 8;
- amdgpu_vm_update_pages(params, pe_start, addr, count,
- AMDGPU_GPU_PAGE_SIZE, flags);
- return;
- }
-
- /* handle the 4K area at the beginning */
- if (pe_start != frag_start) {
- count = (frag_start - pe_start) / 8;
- amdgpu_vm_update_pages(params, pe_start, addr, count,
- AMDGPU_GPU_PAGE_SIZE, flags);
- addr += AMDGPU_GPU_PAGE_SIZE * count;
- }
-
- /* handle the area in the middle */
- count = (frag_end - frag_start) / 8;
- amdgpu_vm_update_pages(params, frag_start, addr, count,
- AMDGPU_GPU_PAGE_SIZE, flags | frag_flags);
-
- /* handle the 4K area at the end */
- if (frag_end != pe_end) {
- addr += AMDGPU_GPU_PAGE_SIZE * count;
- count = (pe_end - frag_end) / 8;
- amdgpu_vm_update_pages(params, frag_end, addr, count,
- AMDGPU_GPU_PAGE_SIZE, flags);
- }
-}
-
-/**
* amdgpu_vm_update_ptes - make sure that page tables are valid
*
* @params: see amdgpu_pte_update_params definition
@@ -796,7 +719,7 @@ static void amdgpu_vm_update_ptes(struct amdgpu_pte_update_params *params,
{
const uint64_t mask = AMDGPU_VM_PTE_COUNT - 1;
- uint64_t cur_pe_start, cur_pe_end, cur_dst;
+ uint64_t cur_pe_start, cur_nptes, cur_dst;
uint64_t addr; /* next GPU address to be updated */
uint64_t pt_idx;
struct amdgpu_bo *pt;
@@ -815,7 +738,7 @@ static void amdgpu_vm_update_ptes(struct amdgpu_pte_update_params *params,
cur_pe_start = amdgpu_bo_gpu_offset(pt);
cur_pe_start += (addr & mask) * 8;
- cur_pe_end = cur_pe_start + 8 * nptes;
+ cur_nptes = nptes;
cur_dst = dst;
/* for next ptb*/
@@ -835,18 +758,19 @@ static void amdgpu_vm_update_ptes(struct amdgpu_pte_update_params *params,
next_pe_start = amdgpu_bo_gpu_offset(pt);
next_pe_start += (addr & mask) * 8;
- if (cur_pe_end == next_pe_start) {
+ if ((cur_pe_start + 8 * cur_nptes) == next_pe_start) {
/* The next ptb is consecutive to current ptb.
- * Don't call amdgpu_vm_frag_ptes now.
+ * Don't call amdgpu_vm_update_pages now.
* Will update two ptbs together in future.
*/
- cur_pe_end += 8 * nptes;
+ cur_nptes += nptes;
} else {
- amdgpu_vm_frag_ptes(params, cur_pe_start, cur_pe_end,
- cur_dst, flags);
+ amdgpu_vm_update_pages(params, cur_pe_start, cur_dst,
+ cur_nptes, AMDGPU_GPU_PAGE_SIZE,
+ flags);
cur_pe_start = next_pe_start;
- cur_pe_end = next_pe_start + 8 * nptes;
+ cur_nptes = nptes;
cur_dst = dst;
}
@@ -855,7 +779,75 @@ static void amdgpu_vm_update_ptes(struct amdgpu_pte_update_params *params,
dst += nptes * AMDGPU_GPU_PAGE_SIZE;
}
- amdgpu_vm_frag_ptes(params, cur_pe_start, cur_pe_end, cur_dst, flags);
+ amdgpu_vm_update_pages(params, cur_pe_start, cur_dst, cur_nptes,
+ AMDGPU_GPU_PAGE_SIZE, flags);
+}
+
+/*
+ * amdgpu_vm_frag_ptes - add fragment information to PTEs
+ *
+ * @params: see amdgpu_pte_update_params definition
+ * @vm: requested vm
+ * @start: first PTE to handle
+ * @end: last PTE to handle
+ * @dst: addr those PTEs should point to
+ * @flags: hw mapping flags
+ */
+static void amdgpu_vm_frag_ptes(struct amdgpu_pte_update_params *params,
+ struct amdgpu_vm *vm,
+ uint64_t start, uint64_t end,
+ uint64_t dst, uint32_t flags)
+{
+ /**
+ * The MC L1 TLB supports variable sized pages, based on a fragment
+ * field in the PTE. When this field is set to a non-zero value, page
+ * granularity is increased from 4KB to (1 << (12 + frag)). The PTE
+ * flags are considered valid for all PTEs within the fragment range
+ * and corresponding mappings are assumed to be physically contiguous.
+ *
+ * The L1 TLB can store a single PTE for the whole fragment,
+ * significantly increasing the space available for translation
+ * caching. This leads to large improvements in throughput when the
+ * TLB is under pressure.
+ *
+ * The L2 TLB distributes small and large fragments into two
+ * asymmetric partitions. The large fragment cache is significantly
+ * larger. Thus, we try to use large fragments wherever possible.
+ * Userspace can support this by aligning virtual base address and
+ * allocation size to the fragment size.
+ */
+
+ /* SI and newer are optimized for 64KB */
+ uint64_t frag_flags = AMDGPU_PTE_FRAG(AMDGPU_LOG2_PAGES_PER_FRAG);
+ uint64_t frag_align = 1 << AMDGPU_LOG2_PAGES_PER_FRAG;
+
+ uint64_t frag_start = ALIGN(start, frag_align);
+ uint64_t frag_end = end & ~(frag_align - 1);
+
+ /* system pages are non continuously */
+ if (params->src || params->pages_addr || !(flags & AMDGPU_PTE_VALID) ||
+ (frag_start >= frag_end)) {
+
+ amdgpu_vm_update_ptes(params, vm, start, end, dst, flags);
+ return;
+ }
+
+ /* handle the 4K area at the beginning */
+ if (start != frag_start) {
+ amdgpu_vm_update_ptes(params, vm, start, frag_start,
+ dst, flags);
+ dst += (frag_start - start) * AMDGPU_GPU_PAGE_SIZE;
+ }
+
+ /* handle the area in the middle */
+ amdgpu_vm_update_ptes(params, vm, frag_start, frag_end, dst,
+ flags | frag_flags);
+
+ /* handle the 4K area at the end */
+ if (frag_end != end) {
+ dst += (frag_end - frag_start) * AMDGPU_GPU_PAGE_SIZE;
+ amdgpu_vm_update_ptes(params, vm, frag_end, end, dst, flags);
+ }
}
/**
@@ -952,7 +944,7 @@ static int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev,
if (r)
goto error_free;
- amdgpu_vm_update_ptes(¶ms, vm, start, last + 1, addr, flags);
+ amdgpu_vm_frag_ptes(¶ms, vm, start, last + 1, addr, flags);
amdgpu_ring_pad_ib(ring, params.ib);
WARN_ON(params.ib->length_dw > ndw);
--
2.5.0
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