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llama.cpp/ggml/src/ggml-sycl/quants.hpp
2025-07-24 11:09:57 +01:00

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//
// MIT license
// Copyright (C) 2025 Codeplay Software Ltd.
// Copyright (C) 2025 Intel Corporation
// SPDX-License-Identifier: MIT
//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
#ifndef GGML_SYCL_QUANTS_HPP
#define GGML_SYCL_QUANTS_HPP
#include <utility>
#include "ggml-common.h"
#include "ggml.h"
namespace ggml_sycl_reordered {
// The reordered block moves quants (qs) and scales(d) to two
// uniform regions of memory that is contiguous in the same tensor.
// What this means is that instead of having:
// [d0, qs0] [d1, qs1] [d2, qs2] ... [dN, qsN]
// We have:
// [qs0, qs1, qs2, ..., qsN] [d0, d1, d2, ..., dN]
//
// Notes: out-of-bounds qs will run into d values
// Aligment relies on the allocated size of qs
template <ggml_type type> struct block_q_t;
// qk number of weights / quants in a block
// qr number of weights in a byte (described as 'before dequantization')
// for quantization types that has low and high bits split, qr is calculated with
// using the lower bits, e.g for Q6 quants QR6 is 2
// qi number of 32 bit integers needed to represent all the quants from a block (`qs` field)
// See ggml-common.h to see how these are calculated
template <> struct block_q_t<GGML_TYPE_Q4_0> {
struct traits {
static constexpr uint32_t qk = QK4_0;
static constexpr uint32_t qi = QI4_0;
static constexpr uint32_t qr = QR4_0;
static constexpr uint32_t vdr_mmvq = 2;
};
static constexpr std::pair<int, int> get_block_offset(const int block_index, const int /* nblocks */) {
return { block_index * (QK4_0 / QR4_0), 0 };
}
static constexpr std::pair<int, int> get_d_offset(int nrows, int ncols, const int block_index) {
return { (ncols / QR4_0 * nrows) + block_index * sizeof(ggml_half), 0 };
}
static constexpr int block_to_q8_1_ratio() { return traits::qk / QK8_1; }
};
template <> struct block_q_t<GGML_TYPE_Q4_K> {
struct traits {
static constexpr uint32_t qk = QK_K;
static constexpr uint32_t qi = QI4_K;
static constexpr uint32_t qr = QR4_K;
static constexpr uint32_t vdr_mmvq = 2;
};
static constexpr std::pair<int, int> get_block_offset(const int block_index, const int /* nblocks */) {
return { block_index * (traits::qk / traits::qr), 0 };
}
static constexpr std::pair<int, int> get_d_offset(int nrows, int ncols, const int block_index) {
auto nblocks = (nrows * (ncols / QK_K));
return { nblocks * (QK_K / 2) + (block_index * K_SCALE_SIZE),
(nblocks * QK_K / 2) + (nblocks * K_SCALE_SIZE) + (block_index * sizeof(ggml_half2)) };
}
static constexpr int block_to_q8_1_ratio() { return traits::qk / QK8_1; }
};
template <> struct block_q_t<GGML_TYPE_Q6_K> {
struct traits {
static constexpr uint32_t qk = QK_K;
static constexpr uint32_t qi = QI6_K;
static constexpr uint32_t qr = QR6_K;
static constexpr uint32_t vdr_mmvq = 1;
};
static constexpr std::pair<int, int> get_block_offset(const int block_index, const int n_blocks) {
auto low_bits_index = block_index * (QK_K / QR6_K);
// the index of high bits it's after all low bits
auto high_bits_index = n_blocks * (QK_K / 2) + (block_index * (QK_K / 4));
return { low_bits_index, high_bits_index };
}
static constexpr std::pair<int, int> get_d_offset(int nrows, int ncols, const int block_index) {
auto nblocks = (nrows * (ncols / QK_K));
auto total_qs_bytes = nblocks * (QK_K / 2) + nblocks * (QK_K / 4);
auto block_scales = total_qs_bytes + block_index * (QK_K / 16);
auto sb_scale = total_qs_bytes + nblocks * (QK_K / 16) + block_index * sizeof(ggml_half);
return { block_scales, sb_scale };
}
static constexpr int block_to_q8_1_ratio() { return traits::qk / QK8_1; }
};
} // namespace ggml_sycl_reordered
#endif // GGML_SYCL_QUANTS_HPP