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/*
* Copyright (c) 2011 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.
*/
#include <stdlib.h>
#include <math.h>
#include "util/macros.h"
#include "main/macros.h"
#include "compiler/shader_enums.h"
#include "gen_l3_config.h"
/**
* The following diagram shows how we partition the URB:
*
* 16kb or 32kb Rest of the URB space
* __________-__________ _________________-_________________
* / \ / \
* +-------------------------------------------------------------+
* | VS/HS/DS/GS/FS Push | VS/HS/DS/GS URB |
* | Constants | Entries |
* +-------------------------------------------------------------+
*
* Push constants must be stored at the beginning of the URB space,
* while URB entries can be stored anywhere. We choose to lay them
* out in pipeline order (VS -> HS -> DS -> GS).
*/
/**
* Decide how to partition the URB among the various stages.
*
* \param[in] push_constant_bytes - space allocate for push constants.
* \param[in] urb_size_bytes - total size of the URB (from L3 config).
* \param[in] tess_present - are tessellation shaders active?
* \param[in] gs_present - are geometry shaders active?
* \param[in] entry_size - the URB entry size (from the shader compiler)
* \param[out] entries - the number of URB entries for each stage
* \param[out] start - the starting offset for each stage
*/
void
gen_get_urb_config(const struct gen_device_info *devinfo,
unsigned push_constant_bytes, unsigned urb_size_bytes,
bool tess_present, bool gs_present,
const unsigned entry_size[4],
unsigned entries[4], unsigned start[4])
{
const bool active[4] = { true, tess_present, tess_present, gs_present };
/* URB allocations must be done in 8k chunks. */
const unsigned chunk_size_bytes = 8192;
const unsigned push_constant_chunks =
push_constant_bytes / chunk_size_bytes;
const unsigned urb_chunks = urb_size_bytes / chunk_size_bytes;
/* From p35 of the Ivy Bridge PRM (section 1.7.1: 3DSTATE_URB_GS):
*
* VS Number of URB Entries must be divisible by 8 if the VS URB Entry
* Allocation Size is less than 9 512-bit URB entries.
*
* Similar text exists for HS, DS and GS.
*/
unsigned granularity[4];
for (int i = MESA_SHADER_VERTEX; i <= MESA_SHADER_GEOMETRY; i++) {
granularity[i] = (entry_size[i] < 9) ? 8 : 1;
}
unsigned min_entries[4] = {
/* VS has a lower limit on the number of URB entries.
*
* From the Broadwell PRM, 3DSTATE_URB_VS instruction:
* "When tessellation is enabled, the VS Number of URB Entries must be
* greater than or equal to 192."
*/
[MESA_SHADER_VERTEX] = tess_present && devinfo->gen == 8 ?
192 : devinfo->urb.min_entries[MESA_SHADER_VERTEX],
/* There are two constraints on the minimum amount of URB space we can
* allocate:
*
* (1) We need room for at least 2 URB entries, since we always operate
* the GS in DUAL_OBJECT mode.
*
* (2) We can't allocate less than nr_gs_entries_granularity.
*/
[MESA_SHADER_GEOMETRY] = gs_present ? 2 : 0,
[MESA_SHADER_TESS_CTRL] = tess_present ? 1 : 0,
[MESA_SHADER_TESS_EVAL] = tess_present ?
devinfo->urb.min_entries[MESA_SHADER_TESS_EVAL] : 0,
};
/* Min VS Entries isn't a multiple of 8 on Cherryview/Broxton; round up.
* Round them all up.
*/
for (int i = MESA_SHADER_VERTEX; i <= MESA_SHADER_GEOMETRY; i++) {
min_entries[i] = ALIGN(min_entries[i], granularity[i]);
}
unsigned entry_size_bytes[4];
for (int i = MESA_SHADER_VERTEX; i <= MESA_SHADER_GEOMETRY; i++) {
entry_size_bytes[i] = 64 * entry_size[i];
}
/* Initially, assign each stage the minimum amount of URB space it needs,
* and make a note of how much additional space it "wants" (the amount of
* additional space it could actually make use of).
*/
unsigned chunks[4];
unsigned wants[4];
unsigned total_needs = push_constant_chunks;
unsigned total_wants = 0;
for (int i = MESA_SHADER_VERTEX; i <= MESA_SHADER_GEOMETRY; i++) {
if (active[i]) {
chunks[i] = DIV_ROUND_UP(min_entries[i] * entry_size_bytes[i],
chunk_size_bytes);
wants[i] =
DIV_ROUND_UP(devinfo->urb.max_entries[i] * entry_size_bytes[i],
chunk_size_bytes) - chunks[i];
} else {
chunks[i] = 0;
wants[i] = 0;
}
total_needs += chunks[i];
total_wants += wants[i];
}
assert(total_needs <= urb_chunks);
/* Mete out remaining space (if any) in proportion to "wants". */
unsigned remaining_space = MIN2(urb_chunks - total_needs, total_wants);
if (remaining_space > 0) {
for (int i = MESA_SHADER_VERTEX;
total_wants > 0 && i <= MESA_SHADER_TESS_EVAL; i++) {
unsigned additional = (unsigned)
roundf(wants[i] * (((float) remaining_space) / total_wants));
chunks[i] += additional;
remaining_space -= additional;
total_wants -= wants[i];
}
chunks[MESA_SHADER_GEOMETRY] += remaining_space;
}
/* Sanity check that we haven't over-allocated. */
unsigned total_chunks = push_constant_chunks;
for (int i = MESA_SHADER_VERTEX; i <= MESA_SHADER_GEOMETRY; i++) {
total_chunks += chunks[i];
}
assert(total_chunks <= urb_chunks);
/* Finally, compute the number of entries that can fit in the space
* allocated to each stage.
*/
for (int i = MESA_SHADER_VERTEX; i <= MESA_SHADER_GEOMETRY; i++) {
entries[i] = chunks[i] * chunk_size_bytes / entry_size_bytes[i];
/* Since we rounded up when computing wants[], this may be slightly
* more than the maximum allowed amount, so correct for that.
*/
entries[i] = MIN2(entries[i], devinfo->urb.max_entries[i]);
/* Ensure that we program a multiple of the granularity. */
entries[i] = ROUND_DOWN_TO(entries[i], granularity[i]);
/* Finally, sanity check to make sure we have at least the minimum
* number of entries needed for each stage.
*/
assert(entries[i] >= min_entries[i]);
}
/* Lay out the URB in pipeline order: push constants, VS, HS, DS, GS. */
int next = push_constant_chunks;
for (int i = MESA_SHADER_VERTEX; i <= MESA_SHADER_GEOMETRY; i++) {
if (entries[i]) {
start[i] = next;
next += chunks[i];
} else {
/* Just put disabled stages at the beginning. */
start[i] = 0;
}
}
}
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