![Daniel Vetter](/assets/img/avatar_default.png)
We have to do this manually. Somebody had a Great Idea. I've measured speed-ups just a few percent above the noise level (below 5% for the best case), but no slowdows. Chris Wilson measured quite a bit more (10-20% above the usual snb variance) on a more recent and better tuned version of sna, but also recorded a few slow-downs on benchmarks know for uglier amounts of snb-induced variance. v2: Incorporate Ben Widawsky's preliminary review comments and elaborate a bit about the performance impact in the changelog. v3: Add a comment as to why we don't need to check the 3rd memory channel. v4: Fixup whitespace. Acked-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Ben Widawsky <ben@bwidawsk.net> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
500 lines
15 KiB
C
500 lines
15 KiB
C
/*
|
|
* Copyright © 2008 Intel Corporation
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a
|
|
* copy of this software and associated documentation files (the "Software"),
|
|
* to deal in the Software without restriction, including without limitation
|
|
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
|
|
* and/or sell copies of the Software, and to permit persons to whom the
|
|
* Software is furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice (including the next
|
|
* paragraph) shall be included in all copies or substantial portions of the
|
|
* Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
|
|
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
|
|
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
|
|
* IN THE SOFTWARE.
|
|
*
|
|
* Authors:
|
|
* Eric Anholt <eric@anholt.net>
|
|
*
|
|
*/
|
|
|
|
#include "linux/string.h"
|
|
#include "linux/bitops.h"
|
|
#include "drmP.h"
|
|
#include "drm.h"
|
|
#include "i915_drm.h"
|
|
#include "i915_drv.h"
|
|
|
|
/** @file i915_gem_tiling.c
|
|
*
|
|
* Support for managing tiling state of buffer objects.
|
|
*
|
|
* The idea behind tiling is to increase cache hit rates by rearranging
|
|
* pixel data so that a group of pixel accesses are in the same cacheline.
|
|
* Performance improvement from doing this on the back/depth buffer are on
|
|
* the order of 30%.
|
|
*
|
|
* Intel architectures make this somewhat more complicated, though, by
|
|
* adjustments made to addressing of data when the memory is in interleaved
|
|
* mode (matched pairs of DIMMS) to improve memory bandwidth.
|
|
* For interleaved memory, the CPU sends every sequential 64 bytes
|
|
* to an alternate memory channel so it can get the bandwidth from both.
|
|
*
|
|
* The GPU also rearranges its accesses for increased bandwidth to interleaved
|
|
* memory, and it matches what the CPU does for non-tiled. However, when tiled
|
|
* it does it a little differently, since one walks addresses not just in the
|
|
* X direction but also Y. So, along with alternating channels when bit
|
|
* 6 of the address flips, it also alternates when other bits flip -- Bits 9
|
|
* (every 512 bytes, an X tile scanline) and 10 (every two X tile scanlines)
|
|
* are common to both the 915 and 965-class hardware.
|
|
*
|
|
* The CPU also sometimes XORs in higher bits as well, to improve
|
|
* bandwidth doing strided access like we do so frequently in graphics. This
|
|
* is called "Channel XOR Randomization" in the MCH documentation. The result
|
|
* is that the CPU is XORing in either bit 11 or bit 17 to bit 6 of its address
|
|
* decode.
|
|
*
|
|
* All of this bit 6 XORing has an effect on our memory management,
|
|
* as we need to make sure that the 3d driver can correctly address object
|
|
* contents.
|
|
*
|
|
* If we don't have interleaved memory, all tiling is safe and no swizzling is
|
|
* required.
|
|
*
|
|
* When bit 17 is XORed in, we simply refuse to tile at all. Bit
|
|
* 17 is not just a page offset, so as we page an objet out and back in,
|
|
* individual pages in it will have different bit 17 addresses, resulting in
|
|
* each 64 bytes being swapped with its neighbor!
|
|
*
|
|
* Otherwise, if interleaved, we have to tell the 3d driver what the address
|
|
* swizzling it needs to do is, since it's writing with the CPU to the pages
|
|
* (bit 6 and potentially bit 11 XORed in), and the GPU is reading from the
|
|
* pages (bit 6, 9, and 10 XORed in), resulting in a cumulative bit swizzling
|
|
* required by the CPU of XORing in bit 6, 9, 10, and potentially 11, in order
|
|
* to match what the GPU expects.
|
|
*/
|
|
|
|
/**
|
|
* Detects bit 6 swizzling of address lookup between IGD access and CPU
|
|
* access through main memory.
|
|
*/
|
|
void
|
|
i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
|
|
{
|
|
drm_i915_private_t *dev_priv = dev->dev_private;
|
|
uint32_t swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
|
|
uint32_t swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
|
|
|
|
if (INTEL_INFO(dev)->gen >= 6) {
|
|
uint32_t dimm_c0, dimm_c1;
|
|
dimm_c0 = I915_READ(MAD_DIMM_C0);
|
|
dimm_c1 = I915_READ(MAD_DIMM_C1);
|
|
dimm_c0 &= MAD_DIMM_A_SIZE_MASK | MAD_DIMM_B_SIZE_MASK;
|
|
dimm_c1 &= MAD_DIMM_A_SIZE_MASK | MAD_DIMM_B_SIZE_MASK;
|
|
/* Enable swizzling when the channels are populated with
|
|
* identically sized dimms. We don't need to check the 3rd
|
|
* channel because no cpu with gpu attached ships in that
|
|
* configuration. Also, swizzling only makes sense for 2
|
|
* channels anyway. */
|
|
if (dimm_c0 == dimm_c1) {
|
|
swizzle_x = I915_BIT_6_SWIZZLE_9_10;
|
|
swizzle_y = I915_BIT_6_SWIZZLE_9;
|
|
} else {
|
|
swizzle_x = I915_BIT_6_SWIZZLE_NONE;
|
|
swizzle_y = I915_BIT_6_SWIZZLE_NONE;
|
|
}
|
|
} else if (IS_GEN5(dev)) {
|
|
/* On Ironlake whatever DRAM config, GPU always do
|
|
* same swizzling setup.
|
|
*/
|
|
swizzle_x = I915_BIT_6_SWIZZLE_9_10;
|
|
swizzle_y = I915_BIT_6_SWIZZLE_9;
|
|
} else if (IS_GEN2(dev)) {
|
|
/* As far as we know, the 865 doesn't have these bit 6
|
|
* swizzling issues.
|
|
*/
|
|
swizzle_x = I915_BIT_6_SWIZZLE_NONE;
|
|
swizzle_y = I915_BIT_6_SWIZZLE_NONE;
|
|
} else if (IS_MOBILE(dev) || (IS_GEN3(dev) && !IS_G33(dev))) {
|
|
uint32_t dcc;
|
|
|
|
/* On 9xx chipsets, channel interleave by the CPU is
|
|
* determined by DCC. For single-channel, neither the CPU
|
|
* nor the GPU do swizzling. For dual channel interleaved,
|
|
* the GPU's interleave is bit 9 and 10 for X tiled, and bit
|
|
* 9 for Y tiled. The CPU's interleave is independent, and
|
|
* can be based on either bit 11 (haven't seen this yet) or
|
|
* bit 17 (common).
|
|
*/
|
|
dcc = I915_READ(DCC);
|
|
switch (dcc & DCC_ADDRESSING_MODE_MASK) {
|
|
case DCC_ADDRESSING_MODE_SINGLE_CHANNEL:
|
|
case DCC_ADDRESSING_MODE_DUAL_CHANNEL_ASYMMETRIC:
|
|
swizzle_x = I915_BIT_6_SWIZZLE_NONE;
|
|
swizzle_y = I915_BIT_6_SWIZZLE_NONE;
|
|
break;
|
|
case DCC_ADDRESSING_MODE_DUAL_CHANNEL_INTERLEAVED:
|
|
if (dcc & DCC_CHANNEL_XOR_DISABLE) {
|
|
/* This is the base swizzling by the GPU for
|
|
* tiled buffers.
|
|
*/
|
|
swizzle_x = I915_BIT_6_SWIZZLE_9_10;
|
|
swizzle_y = I915_BIT_6_SWIZZLE_9;
|
|
} else if ((dcc & DCC_CHANNEL_XOR_BIT_17) == 0) {
|
|
/* Bit 11 swizzling by the CPU in addition. */
|
|
swizzle_x = I915_BIT_6_SWIZZLE_9_10_11;
|
|
swizzle_y = I915_BIT_6_SWIZZLE_9_11;
|
|
} else {
|
|
/* Bit 17 swizzling by the CPU in addition. */
|
|
swizzle_x = I915_BIT_6_SWIZZLE_9_10_17;
|
|
swizzle_y = I915_BIT_6_SWIZZLE_9_17;
|
|
}
|
|
break;
|
|
}
|
|
if (dcc == 0xffffffff) {
|
|
DRM_ERROR("Couldn't read from MCHBAR. "
|
|
"Disabling tiling.\n");
|
|
swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
|
|
swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
|
|
}
|
|
} else {
|
|
/* The 965, G33, and newer, have a very flexible memory
|
|
* configuration. It will enable dual-channel mode
|
|
* (interleaving) on as much memory as it can, and the GPU
|
|
* will additionally sometimes enable different bit 6
|
|
* swizzling for tiled objects from the CPU.
|
|
*
|
|
* Here's what I found on the G965:
|
|
* slot fill memory size swizzling
|
|
* 0A 0B 1A 1B 1-ch 2-ch
|
|
* 512 0 0 0 512 0 O
|
|
* 512 0 512 0 16 1008 X
|
|
* 512 0 0 512 16 1008 X
|
|
* 0 512 0 512 16 1008 X
|
|
* 1024 1024 1024 0 2048 1024 O
|
|
*
|
|
* We could probably detect this based on either the DRB
|
|
* matching, which was the case for the swizzling required in
|
|
* the table above, or from the 1-ch value being less than
|
|
* the minimum size of a rank.
|
|
*/
|
|
if (I915_READ16(C0DRB3) != I915_READ16(C1DRB3)) {
|
|
swizzle_x = I915_BIT_6_SWIZZLE_NONE;
|
|
swizzle_y = I915_BIT_6_SWIZZLE_NONE;
|
|
} else {
|
|
swizzle_x = I915_BIT_6_SWIZZLE_9_10;
|
|
swizzle_y = I915_BIT_6_SWIZZLE_9;
|
|
}
|
|
}
|
|
|
|
dev_priv->mm.bit_6_swizzle_x = swizzle_x;
|
|
dev_priv->mm.bit_6_swizzle_y = swizzle_y;
|
|
}
|
|
|
|
/* Check pitch constriants for all chips & tiling formats */
|
|
static bool
|
|
i915_tiling_ok(struct drm_device *dev, int stride, int size, int tiling_mode)
|
|
{
|
|
int tile_width;
|
|
|
|
/* Linear is always fine */
|
|
if (tiling_mode == I915_TILING_NONE)
|
|
return true;
|
|
|
|
if (IS_GEN2(dev) ||
|
|
(tiling_mode == I915_TILING_Y && HAS_128_BYTE_Y_TILING(dev)))
|
|
tile_width = 128;
|
|
else
|
|
tile_width = 512;
|
|
|
|
/* check maximum stride & object size */
|
|
if (INTEL_INFO(dev)->gen >= 4) {
|
|
/* i965 stores the end address of the gtt mapping in the fence
|
|
* reg, so dont bother to check the size */
|
|
if (stride / 128 > I965_FENCE_MAX_PITCH_VAL)
|
|
return false;
|
|
} else {
|
|
if (stride > 8192)
|
|
return false;
|
|
|
|
if (IS_GEN3(dev)) {
|
|
if (size > I830_FENCE_MAX_SIZE_VAL << 20)
|
|
return false;
|
|
} else {
|
|
if (size > I830_FENCE_MAX_SIZE_VAL << 19)
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/* 965+ just needs multiples of tile width */
|
|
if (INTEL_INFO(dev)->gen >= 4) {
|
|
if (stride & (tile_width - 1))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/* Pre-965 needs power of two tile widths */
|
|
if (stride < tile_width)
|
|
return false;
|
|
|
|
if (stride & (stride - 1))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/* Is the current GTT allocation valid for the change in tiling? */
|
|
static bool
|
|
i915_gem_object_fence_ok(struct drm_i915_gem_object *obj, int tiling_mode)
|
|
{
|
|
u32 size;
|
|
|
|
if (tiling_mode == I915_TILING_NONE)
|
|
return true;
|
|
|
|
if (INTEL_INFO(obj->base.dev)->gen >= 4)
|
|
return true;
|
|
|
|
if (INTEL_INFO(obj->base.dev)->gen == 3) {
|
|
if (obj->gtt_offset & ~I915_FENCE_START_MASK)
|
|
return false;
|
|
} else {
|
|
if (obj->gtt_offset & ~I830_FENCE_START_MASK)
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* Previous chips need to be aligned to the size of the smallest
|
|
* fence register that can contain the object.
|
|
*/
|
|
if (INTEL_INFO(obj->base.dev)->gen == 3)
|
|
size = 1024*1024;
|
|
else
|
|
size = 512*1024;
|
|
|
|
while (size < obj->base.size)
|
|
size <<= 1;
|
|
|
|
if (obj->gtt_space->size != size)
|
|
return false;
|
|
|
|
if (obj->gtt_offset & (size - 1))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Sets the tiling mode of an object, returning the required swizzling of
|
|
* bit 6 of addresses in the object.
|
|
*/
|
|
int
|
|
i915_gem_set_tiling(struct drm_device *dev, void *data,
|
|
struct drm_file *file)
|
|
{
|
|
struct drm_i915_gem_set_tiling *args = data;
|
|
drm_i915_private_t *dev_priv = dev->dev_private;
|
|
struct drm_i915_gem_object *obj;
|
|
int ret = 0;
|
|
|
|
obj = to_intel_bo(drm_gem_object_lookup(dev, file, args->handle));
|
|
if (&obj->base == NULL)
|
|
return -ENOENT;
|
|
|
|
if (!i915_tiling_ok(dev,
|
|
args->stride, obj->base.size, args->tiling_mode)) {
|
|
drm_gem_object_unreference_unlocked(&obj->base);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (obj->pin_count) {
|
|
drm_gem_object_unreference_unlocked(&obj->base);
|
|
return -EBUSY;
|
|
}
|
|
|
|
if (args->tiling_mode == I915_TILING_NONE) {
|
|
args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
|
|
args->stride = 0;
|
|
} else {
|
|
if (args->tiling_mode == I915_TILING_X)
|
|
args->swizzle_mode = dev_priv->mm.bit_6_swizzle_x;
|
|
else
|
|
args->swizzle_mode = dev_priv->mm.bit_6_swizzle_y;
|
|
|
|
/* Hide bit 17 swizzling from the user. This prevents old Mesa
|
|
* from aborting the application on sw fallbacks to bit 17,
|
|
* and we use the pread/pwrite bit17 paths to swizzle for it.
|
|
* If there was a user that was relying on the swizzle
|
|
* information for drm_intel_bo_map()ed reads/writes this would
|
|
* break it, but we don't have any of those.
|
|
*/
|
|
if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_17)
|
|
args->swizzle_mode = I915_BIT_6_SWIZZLE_9;
|
|
if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_10_17)
|
|
args->swizzle_mode = I915_BIT_6_SWIZZLE_9_10;
|
|
|
|
/* If we can't handle the swizzling, make it untiled. */
|
|
if (args->swizzle_mode == I915_BIT_6_SWIZZLE_UNKNOWN) {
|
|
args->tiling_mode = I915_TILING_NONE;
|
|
args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
|
|
args->stride = 0;
|
|
}
|
|
}
|
|
|
|
mutex_lock(&dev->struct_mutex);
|
|
if (args->tiling_mode != obj->tiling_mode ||
|
|
args->stride != obj->stride) {
|
|
/* We need to rebind the object if its current allocation
|
|
* no longer meets the alignment restrictions for its new
|
|
* tiling mode. Otherwise we can just leave it alone, but
|
|
* need to ensure that any fence register is cleared.
|
|
*/
|
|
i915_gem_release_mmap(obj);
|
|
|
|
obj->map_and_fenceable =
|
|
obj->gtt_space == NULL ||
|
|
(obj->gtt_offset + obj->base.size <= dev_priv->mm.gtt_mappable_end &&
|
|
i915_gem_object_fence_ok(obj, args->tiling_mode));
|
|
|
|
/* Rebind if we need a change of alignment */
|
|
if (!obj->map_and_fenceable) {
|
|
u32 unfenced_alignment =
|
|
i915_gem_get_unfenced_gtt_alignment(dev,
|
|
obj->base.size,
|
|
args->tiling_mode);
|
|
if (obj->gtt_offset & (unfenced_alignment - 1))
|
|
ret = i915_gem_object_unbind(obj);
|
|
}
|
|
|
|
if (ret == 0) {
|
|
obj->tiling_changed = true;
|
|
obj->tiling_mode = args->tiling_mode;
|
|
obj->stride = args->stride;
|
|
}
|
|
}
|
|
/* we have to maintain this existing ABI... */
|
|
args->stride = obj->stride;
|
|
args->tiling_mode = obj->tiling_mode;
|
|
drm_gem_object_unreference(&obj->base);
|
|
mutex_unlock(&dev->struct_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* Returns the current tiling mode and required bit 6 swizzling for the object.
|
|
*/
|
|
int
|
|
i915_gem_get_tiling(struct drm_device *dev, void *data,
|
|
struct drm_file *file)
|
|
{
|
|
struct drm_i915_gem_get_tiling *args = data;
|
|
drm_i915_private_t *dev_priv = dev->dev_private;
|
|
struct drm_i915_gem_object *obj;
|
|
|
|
obj = to_intel_bo(drm_gem_object_lookup(dev, file, args->handle));
|
|
if (&obj->base == NULL)
|
|
return -ENOENT;
|
|
|
|
mutex_lock(&dev->struct_mutex);
|
|
|
|
args->tiling_mode = obj->tiling_mode;
|
|
switch (obj->tiling_mode) {
|
|
case I915_TILING_X:
|
|
args->swizzle_mode = dev_priv->mm.bit_6_swizzle_x;
|
|
break;
|
|
case I915_TILING_Y:
|
|
args->swizzle_mode = dev_priv->mm.bit_6_swizzle_y;
|
|
break;
|
|
case I915_TILING_NONE:
|
|
args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
|
|
break;
|
|
default:
|
|
DRM_ERROR("unknown tiling mode\n");
|
|
}
|
|
|
|
/* Hide bit 17 from the user -- see comment in i915_gem_set_tiling */
|
|
if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_17)
|
|
args->swizzle_mode = I915_BIT_6_SWIZZLE_9;
|
|
if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_10_17)
|
|
args->swizzle_mode = I915_BIT_6_SWIZZLE_9_10;
|
|
|
|
drm_gem_object_unreference(&obj->base);
|
|
mutex_unlock(&dev->struct_mutex);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Swap every 64 bytes of this page around, to account for it having a new
|
|
* bit 17 of its physical address and therefore being interpreted differently
|
|
* by the GPU.
|
|
*/
|
|
static void
|
|
i915_gem_swizzle_page(struct page *page)
|
|
{
|
|
char temp[64];
|
|
char *vaddr;
|
|
int i;
|
|
|
|
vaddr = kmap(page);
|
|
|
|
for (i = 0; i < PAGE_SIZE; i += 128) {
|
|
memcpy(temp, &vaddr[i], 64);
|
|
memcpy(&vaddr[i], &vaddr[i + 64], 64);
|
|
memcpy(&vaddr[i + 64], temp, 64);
|
|
}
|
|
|
|
kunmap(page);
|
|
}
|
|
|
|
void
|
|
i915_gem_object_do_bit_17_swizzle(struct drm_i915_gem_object *obj)
|
|
{
|
|
int page_count = obj->base.size >> PAGE_SHIFT;
|
|
int i;
|
|
|
|
if (obj->bit_17 == NULL)
|
|
return;
|
|
|
|
for (i = 0; i < page_count; i++) {
|
|
char new_bit_17 = page_to_phys(obj->pages[i]) >> 17;
|
|
if ((new_bit_17 & 0x1) !=
|
|
(test_bit(i, obj->bit_17) != 0)) {
|
|
i915_gem_swizzle_page(obj->pages[i]);
|
|
set_page_dirty(obj->pages[i]);
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
i915_gem_object_save_bit_17_swizzle(struct drm_i915_gem_object *obj)
|
|
{
|
|
int page_count = obj->base.size >> PAGE_SHIFT;
|
|
int i;
|
|
|
|
if (obj->bit_17 == NULL) {
|
|
obj->bit_17 = kmalloc(BITS_TO_LONGS(page_count) *
|
|
sizeof(long), GFP_KERNEL);
|
|
if (obj->bit_17 == NULL) {
|
|
DRM_ERROR("Failed to allocate memory for bit 17 "
|
|
"record\n");
|
|
return;
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < page_count; i++) {
|
|
if (page_to_phys(obj->pages[i]) & (1 << 17))
|
|
__set_bit(i, obj->bit_17);
|
|
else
|
|
__clear_bit(i, obj->bit_17);
|
|
}
|
|
}
|