kv-cache : support attention rotation for heterogeneous iSWA (#21513)

* kv-cache : support attention rotation for heterogeneous iSWA

* cont : remove assert
This commit is contained in:
Georgi Gerganov
2026-04-07 20:31:28 +03:00
committed by GitHub
parent 957d717ce5
commit 4eb19514dd
4 changed files with 58 additions and 17 deletions
+18 -6
View File
@@ -169,6 +169,18 @@ llama_kv_cache::llama_kv_cache(
continue;
}
if (n_embd_head_k_all == 0) {
n_embd_head_k_all = (int32_t) hparams.n_embd_head_k(il);
} else if (n_embd_head_k_all > 0 && n_embd_head_k_all != (int32_t) hparams.n_embd_head_k(il)) {
n_embd_head_k_all = -1;
}
if (n_embd_head_v_all == 0) {
n_embd_head_v_all = (int32_t) hparams.n_embd_head_v(il);
} else if (n_embd_head_v_all > 0 && n_embd_head_v_all != (int32_t) hparams.n_embd_head_v(il)) {
n_embd_head_v_all = -1;
}
// [TAG_V_CACHE_VARIABLE]
const uint32_t n_embd_k_gqa = hparams.n_embd_k_gqa(il);
const uint32_t n_embd_v_gqa = !v_trans ? hparams.n_embd_v_gqa(il) : hparams.n_embd_v_gqa_max();
@@ -276,23 +288,23 @@ llama_kv_cache::llama_kv_cache(
attn_rot_k =
!attn_rot_disable &&
n_embd_head_k_all > 0 &&
ggml_is_quantized(type_k) &&
!hparams.is_n_embd_k_gqa_variable() &&
hparams.n_embd_head_k() % 64 == 0;
attn_rot_v =
!attn_rot_disable &&
n_embd_head_v_all > 0 &&
ggml_is_quantized(type_v) &&
!hparams.is_n_embd_v_gqa_variable() &&
hparams.n_embd_head_v() % 64 == 0;
LLAMA_LOG_INFO("%s: attn_rot_k = %d\n", __func__, attn_rot_k);
LLAMA_LOG_INFO("%s: attn_rot_v = %d\n", __func__, attn_rot_v);
LLAMA_LOG_INFO("%s: attn_rot_k = %d, n_embd_head_k_all = %d\n", __func__, attn_rot_k, n_embd_head_k_all);
LLAMA_LOG_INFO("%s: attn_rot_v = %d, n_embd_head_k_all = %d\n", __func__, attn_rot_v, n_embd_head_v_all);
// pre-compute the haramard matrices and keep them in host memory
// TODO: in the future, we can make copies in the backend buffers to avoid host -> device transfers
if (attn_rot_k || attn_rot_v) {
for (int64_t n = 64; n <= std::max(hparams.n_embd_head_k(), hparams.n_embd_head_v()); n *= 2) {
for (int64_t n = 64; n <= std::max(n_embd_head_k_all, n_embd_head_v_all); n *= 2) {
attn_rot_hadamard[n] = std::vector<float>(n*n);
ggml_init_params params = {
@@ -1308,7 +1320,7 @@ ggml_tensor * llama_kv_cache::build_input_k_rot(ggml_context * ctx) const {
// ref: https://github.com/ggml-org/llama.cpp/pull/21038#issuecomment-4141323088
do {
nrot *= 2;
} while (hparams.n_embd_head_k() % nrot == 0);
} while (n_embd_head_k_all % nrot == 0);
nrot /= 2;
res = ggml_new_tensor_2d(ctx, GGML_TYPE_F32, nrot, nrot);