broadcom/vc5: Add support for register spilling.
Our register spilling support is nice to have since vc4 couldn't at all, but we're still very restricted due to needing to not spill during a TMU operation, or during the last segment of the program (which would be nice to spill a value of, when there's a long-lived value being passed through with little modification from the start to the end). We could do better by emitting unspills for the last-segment values just before the last thrsw, since the last segment is probably not the maximum interference area. Fixes GTF uniform_buffer_object_arrays_of_all_valid_basic_types and 3 others.
This commit is contained in:
@@ -1919,12 +1919,11 @@ vir_remove_thrsw(struct v3d_compile *c)
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vir_remove_instruction(c, inst);
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}
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}
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vir_calculate_live_intervals(c);
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c->last_thrsw = NULL;
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}
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static void
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void
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vir_emit_last_thrsw(struct v3d_compile *c)
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{
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/* On V3D before 4.1, we need a TMU op to be outstanding when thread
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@@ -2012,16 +2011,16 @@ v3d_nir_to_vir(struct v3d_compile *c)
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fprintf(stderr, "\n");
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}
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/* Compute the live ranges so we can figure out interference. */
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vir_calculate_live_intervals(c);
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/* Attempt to allocate registers for the temporaries. If we fail,
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* reduce thread count and try again.
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*/
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int min_threads = (c->devinfo->ver >= 41) ? 2 : 1;
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struct qpu_reg *temp_registers;
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while (true) {
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temp_registers = v3d_register_allocate(c);
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bool spilled;
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temp_registers = v3d_register_allocate(c, &spilled);
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if (spilled)
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continue;
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if (temp_registers)
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break;
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@@ -248,6 +248,12 @@ enum quniform_contents {
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QUNIFORM_ALPHA_REF,
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QUNIFORM_SAMPLE_MASK,
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/**
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* Returns the the offset of the scratch buffer for register spilling.
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*/
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QUNIFORM_SPILL_OFFSET,
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QUNIFORM_SPILL_SIZE_PER_THREAD,
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};
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struct v3d_varying_slot {
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@@ -506,6 +512,20 @@ struct v3d_compile {
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uint8_t vattr_sizes[V3D_MAX_VS_INPUTS];
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uint32_t num_vpm_writes;
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/* Size in bytes of registers that have been spilled. This is how much
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* space needs to be available in the spill BO per thread per QPU.
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*/
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uint32_t spill_size;
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/* Shader-db stats for register spilling. */
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uint32_t spills, fills;
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/**
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* Register spilling's per-thread base address, shared between each
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* spill/fill's addressing calculations.
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*/
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struct qreg spill_base;
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/* Bit vector of which temps may be spilled */
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BITSET_WORD *spillable;
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/**
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* Array of the VARYING_SLOT_* of all FS QFILE_VARY reads.
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*
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@@ -600,6 +620,7 @@ struct v3d_prog_data {
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struct v3d_ubo_range *ubo_ranges;
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uint32_t num_ubo_ranges;
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uint32_t ubo_size;
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uint32_t spill_size;
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uint8_t num_inputs;
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uint8_t threads;
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@@ -697,6 +718,7 @@ void vir_set_unpack(struct qinst *inst, int src,
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enum v3d_qpu_input_unpack unpack);
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struct qreg vir_get_temp(struct v3d_compile *c);
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void vir_emit_last_thrsw(struct v3d_compile *c);
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void vir_calculate_live_intervals(struct v3d_compile *c);
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bool vir_has_implicit_uniform(struct qinst *inst);
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int vir_get_implicit_uniform_src(struct qinst *inst);
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@@ -746,7 +768,7 @@ void v3d40_vir_emit_tex(struct v3d_compile *c, nir_tex_instr *instr);
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void v3d_vir_to_qpu(struct v3d_compile *c, struct qpu_reg *temp_registers);
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uint32_t v3d_qpu_schedule_instructions(struct v3d_compile *c);
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void qpu_validate(struct v3d_compile *c);
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struct qpu_reg *v3d_register_allocate(struct v3d_compile *c);
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struct qpu_reg *v3d_register_allocate(struct v3d_compile *c, bool *spilled);
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bool vir_init_reg_sets(struct v3d_compiler *compiler);
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void vir_PF(struct v3d_compile *c, struct qreg src, enum v3d_qpu_pf pf);
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@@ -354,10 +354,17 @@ vir_get_temp(struct v3d_compile *c)
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if (c->num_temps > c->defs_array_size) {
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uint32_t old_size = c->defs_array_size;
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c->defs_array_size = MAX2(old_size * 2, 16);
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c->defs = reralloc(c, c->defs, struct qinst *,
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c->defs_array_size);
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memset(&c->defs[old_size], 0,
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sizeof(c->defs[0]) * (c->defs_array_size - old_size));
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c->spillable = reralloc(c, c->spillable,
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BITSET_WORD,
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BITSET_WORDS(c->defs_array_size));
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for (int i = old_size; i < c->defs_array_size; i++)
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BITSET_SET(c->spillable, i);
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}
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return reg;
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@@ -653,6 +660,7 @@ v3d_set_prog_data(struct v3d_compile *c,
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{
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prog_data->threads = c->threads;
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prog_data->single_seg = !c->last_thrsw;
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prog_data->spill_size = c->spill_size;
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v3d_set_prog_data_uniforms(c, prog_data);
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v3d_set_prog_data_ubo(c, prog_data);
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@@ -33,6 +33,211 @@
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#define PHYS_INDEX (ACC_INDEX + ACC_COUNT)
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#define PHYS_COUNT 64
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static bool
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is_last_ldtmu(struct qinst *inst, struct qblock *block)
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{
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list_for_each_entry_from(struct qinst, scan_inst, inst,
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&block->instructions, link) {
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if (inst->qpu.sig.ldtmu)
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return false;
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if (v3d_qpu_writes_tmu(&inst->qpu))
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return true;
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}
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return true;
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}
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static int
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v3d_choose_spill_node(struct v3d_compile *c, struct ra_graph *g,
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uint32_t *temp_to_node)
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{
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float block_scale = 1.0;
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float spill_costs[c->num_temps];
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bool in_tmu_operation = false;
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bool started_last_seg = false;
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for (unsigned i = 0; i < c->num_temps; i++)
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spill_costs[i] = 0.0;
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/* XXX: Scale the cost up when inside of a loop. */
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vir_for_each_block(block, c) {
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vir_for_each_inst(inst, block) {
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/* We can't insert a new TMU operation while currently
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* in a TMU operation, and we can't insert new thread
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* switches after starting output writes.
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*/
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bool no_spilling =
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(in_tmu_operation ||
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(c->threads > 1 && started_last_seg));
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for (int i = 0; i < vir_get_nsrc(inst); i++) {
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if (inst->src[i].file != QFILE_TEMP)
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continue;
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int temp = inst->src[i].index;
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if (no_spilling) {
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BITSET_CLEAR(c->spillable,
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temp);
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} else {
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spill_costs[temp] += block_scale;
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}
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}
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if (inst->dst.file == QFILE_TEMP) {
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int temp = inst->dst.index;
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if (no_spilling) {
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BITSET_CLEAR(c->spillable,
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temp);
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} else {
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spill_costs[temp] += block_scale;
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}
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}
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if (inst->is_last_thrsw)
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started_last_seg = true;
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if (v3d_qpu_writes_vpm(&inst->qpu) ||
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v3d_qpu_uses_tlb(&inst->qpu))
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started_last_seg = true;
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/* Track when we're in between a TMU setup and the
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* final LDTMU from that TMU setup. We can't
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* spill/fill any temps during that time, because that
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* involves inserting a new TMU setup/LDTMU sequence.
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*/
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if (inst->qpu.sig.ldtmu &&
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is_last_ldtmu(inst, block))
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in_tmu_operation = false;
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if (v3d_qpu_writes_tmu(&inst->qpu))
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in_tmu_operation = true;
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}
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}
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for (unsigned i = 0; i < c->num_temps; i++) {
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int node = temp_to_node[i];
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if (BITSET_TEST(c->spillable, i))
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ra_set_node_spill_cost(g, node, spill_costs[i]);
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}
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return ra_get_best_spill_node(g);
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}
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/* The spill offset for this thread takes a bit of setup, so do it once at
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* program start.
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*/
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static void
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v3d_setup_spill_base(struct v3d_compile *c)
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{
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c->cursor = vir_before_block(vir_entry_block(c));
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int start_num_temps = c->num_temps;
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/* Each thread wants to be in a separate region of the scratch space
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* so that the QPUs aren't fighting over cache lines. We have the
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* driver keep a single global spill BO rather than
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* per-spilling-program BOs, so we need a uniform from the driver for
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* what the per-thread scale is.
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*/
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struct qreg thread_offset =
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vir_UMUL(c,
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vir_TIDX(c),
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vir_uniform(c, QUNIFORM_SPILL_SIZE_PER_THREAD, 0));
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/* Each channel in a reg is 4 bytes, so scale them up by that. */
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struct qreg element_offset = vir_SHL(c, vir_EIDX(c),
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vir_uniform_ui(c, 2));
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c->spill_base = vir_ADD(c,
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vir_ADD(c, thread_offset, element_offset),
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vir_uniform(c, QUNIFORM_SPILL_OFFSET, 0));
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/* Make sure that we don't spill the spilling setup instructions. */
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for (int i = start_num_temps; i < c->num_temps; i++)
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BITSET_CLEAR(c->spillable, i);
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}
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static void
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v3d_emit_spill_tmua(struct v3d_compile *c, uint32_t spill_offset)
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{
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vir_ADD_dest(c, vir_reg(QFILE_MAGIC,
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V3D_QPU_WADDR_TMUA),
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c->spill_base,
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vir_uniform_ui(c, spill_offset));
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}
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static void
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v3d_spill_reg(struct v3d_compile *c, int spill_temp)
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{
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uint32_t spill_offset = c->spill_size;
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c->spill_size += 16 * sizeof(uint32_t);
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if (spill_offset == 0)
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v3d_setup_spill_base(c);
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struct qinst *last_thrsw = c->last_thrsw;
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assert(!last_thrsw || last_thrsw->is_last_thrsw);
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int start_num_temps = c->num_temps;
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vir_for_each_inst_inorder(inst, c) {
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for (int i = 0; i < vir_get_nsrc(inst); i++) {
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if (inst->src[i].file != QFILE_TEMP ||
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inst->src[i].index != spill_temp) {
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continue;
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}
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c->cursor = vir_before_inst(inst);
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v3d_emit_spill_tmua(c, spill_offset);
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vir_emit_thrsw(c);
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inst->src[i] = vir_LDTMU(c);
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c->fills++;
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}
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if (inst->dst.file == QFILE_TEMP &&
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inst->dst.index == spill_temp) {
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c->cursor = vir_after_inst(inst);
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inst->dst.index = c->num_temps++;
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vir_MOV_dest(c, vir_reg(QFILE_MAGIC, V3D_QPU_WADDR_TMUD),
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inst->dst);
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v3d_emit_spill_tmua(c, spill_offset);
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vir_emit_thrsw(c);
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c->spills++;
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}
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/* If we didn't have a last-thrsw inserted by nir_to_vir and
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* we've been inserting thrsws, then insert a new last_thrsw
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* right before we start the vpm/tlb sequence for the last
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* thread segment.
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*/
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if (!last_thrsw && c->last_thrsw &&
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(v3d_qpu_writes_vpm(&inst->qpu) ||
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v3d_qpu_uses_tlb(&inst->qpu))) {
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c->cursor = vir_before_inst(inst);
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vir_emit_thrsw(c);
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last_thrsw = c->last_thrsw;
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last_thrsw->is_last_thrsw = true;
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}
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}
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/* Make sure c->last_thrsw is the actual last thrsw, not just one we
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* inserted in our most recent unspill.
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*/
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if (last_thrsw)
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c->last_thrsw = last_thrsw;
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/* Don't allow spilling of our spilling instructions. There's no way
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* they can help get things colored.
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*/
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for (int i = start_num_temps; i < c->num_temps; i++)
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BITSET_CLEAR(c->spillable, i);
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}
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bool
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vir_init_reg_sets(struct v3d_compiler *compiler)
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{
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@@ -96,7 +301,7 @@ node_to_temp_priority(const void *in_a, const void *in_b)
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* The return value should be freed by the caller.
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*/
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struct qpu_reg *
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v3d_register_allocate(struct v3d_compile *c)
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v3d_register_allocate(struct v3d_compile *c, bool *spilled)
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{
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struct node_to_temp_map map[c->num_temps];
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uint32_t temp_to_node[c->num_temps];
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@@ -105,9 +310,10 @@ v3d_register_allocate(struct v3d_compile *c)
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sizeof(*temp_registers));
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int acc_nodes[ACC_COUNT];
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struct ra_graph *g = ra_alloc_interference_graph(c->compiler->regs,
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c->num_temps +
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ARRAY_SIZE(acc_nodes));
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*spilled = false;
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vir_calculate_live_intervals(c);
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/* Convert 1, 2, 4 threads to 0, 1, 2 index.
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*
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* V3D 4.x has double the physical register space, so 64 physical regs
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@@ -119,6 +325,10 @@ v3d_register_allocate(struct v3d_compile *c)
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thread_index--;
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}
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struct ra_graph *g = ra_alloc_interference_graph(c->compiler->regs,
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c->num_temps +
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ARRAY_SIZE(acc_nodes));
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/* Make some fixed nodes for the accumulators, which we will need to
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* interfere with when ops have implied r3/r4 writes or for the thread
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* switches. We could represent these as classes for the nodes to
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@@ -254,6 +464,20 @@ v3d_register_allocate(struct v3d_compile *c)
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bool ok = ra_allocate(g);
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if (!ok) {
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/* Try to spill, if we can't reduce threading first. */
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if (thread_index == 0) {
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int node = v3d_choose_spill_node(c, g, temp_to_node);
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if (node != -1) {
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v3d_spill_reg(c, map[node].temp);
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ralloc_free(g);
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/* Ask the outer loop to call back in. */
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*spilled = true;
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return NULL;
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}
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}
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free(temp_registers);
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return NULL;
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}
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@@ -280,5 +504,17 @@ v3d_register_allocate(struct v3d_compile *c)
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ralloc_free(g);
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if (V3D_DEBUG & V3D_DEBUG_SHADERDB) {
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fprintf(stderr, "SHADER-DB: %s prog %d/%d: %d spills\n",
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vir_get_stage_name(c),
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c->program_id, c->variant_id,
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c->spills);
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fprintf(stderr, "SHADER-DB: %s prog %d/%d: %d fills\n",
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vir_get_stage_name(c),
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c->program_id, c->variant_id,
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c->fills);
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}
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return temp_registers;
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}
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@@ -154,6 +154,9 @@ struct vc5_compiled_shader {
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struct vc5_program_stateobj {
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struct vc5_uncompiled_shader *bind_vs, *bind_fs;
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struct vc5_compiled_shader *cs, *vs, *fs;
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struct vc5_bo *spill_bo;
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int spill_size_per_thread;
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};
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struct vc5_constbuf_stateobj {
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@@ -267,6 +267,21 @@ vc5_get_compiled_shader(struct vc5_context *vc5, struct v3d_key *key)
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memcpy(dup_key, key, key_size);
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_mesa_hash_table_insert(ht, dup_key, shader);
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if (shader->prog_data.base->spill_size >
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vc5->prog.spill_size_per_thread) {
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/* Max 4 QPUs per slice, 3 slices per core. We only do single
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* core so far. This overallocates memory on smaller cores.
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*/
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int total_spill_size =
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4 * 3 * shader->prog_data.base->spill_size;
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vc5_bo_unreference(&vc5->prog.spill_bo);
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vc5->prog.spill_bo = vc5_bo_alloc(vc5->screen,
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total_spill_size, "spill");
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vc5->prog.spill_size_per_thread =
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shader->prog_data.base->spill_size;
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}
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return shader;
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}
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||||
|
||||
|
@@ -389,6 +389,16 @@ vc5_write_uniforms(struct vc5_context *vc5, struct vc5_compiled_shader *shader,
|
||||
/* XXX */
|
||||
break;
|
||||
|
||||
case QUNIFORM_SPILL_OFFSET:
|
||||
cl_aligned_reloc(&job->indirect, &uniforms,
|
||||
vc5->prog.spill_bo, 0);
|
||||
break;
|
||||
|
||||
case QUNIFORM_SPILL_SIZE_PER_THREAD:
|
||||
cl_aligned_u32(&uniforms,
|
||||
vc5->prog.spill_size_per_thread);
|
||||
break;
|
||||
|
||||
default:
|
||||
assert(quniform_contents_is_texture_p0(uinfo->contents[i]));
|
||||
|
||||
@@ -451,6 +461,8 @@ vc5_set_shader_uniform_dirty_flags(struct vc5_compiled_shader *shader)
|
||||
case QUNIFORM_TEXTURE_DEPTH:
|
||||
case QUNIFORM_TEXTURE_ARRAY_SIZE:
|
||||
case QUNIFORM_TEXTURE_LEVELS:
|
||||
case QUNIFORM_SPILL_OFFSET:
|
||||
case QUNIFORM_SPILL_SIZE_PER_THREAD:
|
||||
/* We could flag this on just the stage we're
|
||||
* compiling for, but it's not passed in.
|
||||
*/
|
||||
|
Reference in New Issue
Block a user