Batched gemm for grid IQ quants

Style updates and a bit more performance

Clean up comments

Move code around

Vectorize IQ panel decode, lower threshold for speedup

IQ panel: single-source gather layout, gate bias, vectorize interleave

Add ggml_gemm_iqp_8x8_q8_K_p4 kernel, remove gather buffer

Move IQ panel code out of repack into iqp.cpp, clean up comments

Another comment sweep

ggml/src/ggml-common.h

@@ -1131,7 +1131,7 @@ GGML_TABLE_END()
 #define NGRID_IQ1S 2048
 #define IQ1S_DELTA 0.125f
 #define IQ1M_DELTA 0.125f
-#if defined(GGML_COMMON_IMPL_C)
+#if defined(GGML_COMMON_IMPL_C) || defined(GGML_COMMON_IMPL_CPP)
 GGML_TABLE_BEGIN(uint64_t, iq1s_grid, NGRID_IQ1S)
     0xffffffffffffffff, 0xffffffffffffff01, 0xffffffffffff0000, 0xffffffffffff01ff,
     0xffffffffffff0101, 0xffffffffff00ff00, 0xffffffffff000000, 0xffffffffff01ffff,

ggml/src/ggml-cpu/CMakeLists.txt

@@ -31,6 +31,8 @@ function(ggml_add_cpu_backend_variant_impl tag_name)
         ggml-cpu/ggml-cpu.cpp
         ggml-cpu/repack.cpp
         ggml-cpu/repack.h
+        ggml-cpu/iqp.cpp
+        ggml-cpu/iqp.h
         ggml-cpu/hbm.cpp
         ggml-cpu/hbm.h
         ggml-cpu/quants.c

ggml/src/ggml-cpu/ggml-cpu.c

@@ -4,6 +4,7 @@
 #include "ggml-backend-impl.h"
 #include "ggml-backend.h"
 #include "traits.h"
+#include "iqp.h"
 #include "ggml-cpu-impl.h"
 #include "ggml-impl.h"
 #include "quants.h"
@@ -1363,6 +1364,13 @@ UseGgmlGemm1:;
 
     ggml_barrier(params->threadpool);
 
+    // IQ panel gemm (see iqp.h) - must come after the barrier above, it consumes the q8_K rows
+    // of src1 from the work buffer
+    if (ggml_cpu_iqp_supported_mul_mat(dst) && !params->use_ref) {
+        ggml_compute_forward_mul_mat_iqp(params, dst);
+        return;
+    }
+
 #if GGML_USE_LLAMAFILE
     if (src1->type != vec_dot_type) {
         const void* wdata = (src1->type == vec_dot_type) ? src1->data : params->wdata;
@@ -1580,6 +1588,16 @@ static void ggml_compute_forward_mul_mat_id(
     char (*atomic_current_chunk)[CACHE_LINE_SIZE] = // [n_as]
         incr_ptr_aligned(&wdata_cur, CACHE_LINE_SIZE * n_as, CACHE_LINE_SIZE);
 
+    // IQ panel gemm (see iqp.h); per expert eligibility is decided below, but the work buffer is
+    // reserved for the whole node (ggml_graph_plan sizes it without params, use_ref only skips the dispatch)
+    const bool iqp = ggml_cpu_iqp_supported_mul_mat_id(dst) && !params->use_ref;
+
+    char * iqp_panels = NULL;
+
+    if (iqp) {
+        iqp_panels = incr_ptr_aligned(&wdata_cur, nth * ggml_cpu_iqp_scratch_size(dst), 64);
+    }
+
     GGML_ASSERT(params->wsize >= (size_t)((char *) wdata_cur - (char *) params->wdata));
 
     if (src1->type != vec_dot_type) {
@@ -1651,6 +1669,13 @@ static void ggml_compute_forward_mul_mat_id(
             continue;
         }
 
+        if (iqp && ggml_cpu_iqp_expert_eligible(cne1)) {
+            ggml_compute_forward_mul_mat_id_iqp(params, dst, cur_a, cne1, (const int32_t *) &MMID_MATRIX_ROW(cur_a, 0),
+                                                iqp_panels);
+
+            continue;
+        }
+
         const char * src0_cur = (const char *) src0->data + cur_a * nb02;
         const void * wdata = (src1->type == vec_dot_type) ? src1->data : params->wdata;
         const size_t row_size = ggml_row_size(vec_dot_type, ne10);
@@ -2857,6 +2882,12 @@ struct ggml_cplan ggml_graph_plan(
                         if (node->src[1]->type != vec_dot_type) {
                             cur = ggml_row_size(vec_dot_type, ggml_nelements(node->src[1]));
                         }
+
+                        // the IQ panel path needs one scratch panel per thread past the q8_K rows
+                        if (ggml_cpu_iqp_supported_mul_mat(node)) {
+                            cur =
+                                MAX(cur, ggml_cpu_iqp_scratch_offset(node) + n_tasks * ggml_cpu_iqp_scratch_size(node));
+                        }
                     } break;
                 case GGML_OP_MUL_MAT_ID:
                     {
@@ -2876,6 +2907,10 @@ struct ggml_cplan ggml_graph_plan(
                         cur += n_as*ids->ne[0]*ids->ne[1]*sizeof(struct mmid_row_mapping) + sizeof(int64_t);
                         // atomic_current_chunk
                         cur += CACHE_LINE_SIZE*n_as + CACHE_LINE_SIZE;
+                        // the IQ panel path needs one scratch panel per thread on top of that
+                        if (ggml_cpu_iqp_supported_mul_mat_id(node)) {
+                            cur += n_tasks * ggml_cpu_iqp_scratch_size(node) + 64;
+                        }
                     } break;
                 case GGML_OP_OUT_PROD:
                     {

ggml/src/ggml-cpu/iqp.h

@@ -0,0 +1,55 @@
+#pragma once
+
+#include "ggml-cpu-impl.h"
+#include "ggml.h"
+
+// GGML internal header
+
+// batched mul_mat path for the grid based IQ types: decode 8 src0 rows at a time into per thread scratch
+// (block_iqp_x8, see iqp.cpp) and run an integer gemm over them against all src1 columns
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// smallest src1 batch for which the decode pays for itself
+#define GGML_IQP_MIN_BATCH 8
+
+// same, per expert, for MUL_MAT_ID
+#define GGML_IQP_MIN_BATCH_ID 8
+
+static inline bool ggml_cpu_iqp_expert_eligible(int64_t cne1) {
+    return cne1 >= GGML_IQP_MIN_BATCH_ID;
+}
+
+static inline size_t ggml_cpu_iqp_row_size(const struct ggml_tensor * dst) {
+    return ggml_row_size(GGML_TYPE_Q8_K, dst->src[1]->ne[0]);
+}
+
+bool ggml_cpu_iqp_supported_mul_mat(const struct ggml_tensor * dst);
+
+// node level test only - per expert eligibility is decided with ggml_cpu_iqp_expert_eligible
+bool ggml_cpu_iqp_supported_mul_mat_id(const struct ggml_tensor * dst);
+
+size_t ggml_cpu_iqp_src1_conv_size(const struct ggml_tensor * dst);
+
+// offset of the panel scratch area inside the work buffer (past the q8_K conversion of src1)
+size_t ggml_cpu_iqp_scratch_offset(const struct ggml_tensor * dst);
+
+// per thread panel scratch bytes, padded
+size_t ggml_cpu_iqp_scratch_size(const struct ggml_tensor * dst);
+
+// must be called after src1 has been converted to q8_K into params->wdata and the threads have synchronized on it
+void ggml_compute_forward_mul_mat_iqp(const struct ggml_compute_params * params, struct ggml_tensor * dst);
+
+// one expert: expert_rows points at its row of the matrix_rows table of (i1, i2) int32 pairs, panels at the base of the per thread panel scratches
+void ggml_compute_forward_mul_mat_id_iqp(const struct ggml_compute_params * params,
+                                         struct ggml_tensor *               dst,
+                                         int64_t                            cur_a,
+                                         int64_t                            cne1,
+                                         const int32_t *                    expert_rows,
+                                         void *                             panels);
+
+#ifdef __cplusplus
+}
+#endif