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CANN: Add ROPE sin/cos cache for reuse (llama/15912)
* CANN: Add ROPE sin/cos cache for reuse Introduce sin/cos caching mechanism in ROPE to avoid redundant computation across layers. The cache is built on the first layer per device and reused by subsequent layers if parameters match. - Added sin_cache / cos_cache pointers and position_length tracking - Introduced cache validity flags and properties: (ext_factor, theta_scale, freq_scale, attn_factor, is_neox) - Accelerates ROPE by eliminating repeated sin/cos generation This change reduces overhead in multi-layer scenarios while preserving correctness by verifying parameter consistency. Co-authored-by: hipudding <[email protected]> * fix typo Signed-off-by: noemotiovon <[email protected]> --------- Signed-off-by: noemotiovon <[email protected]> Co-authored-by: hipudding <[email protected]>
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src/ggml-cann/aclnn_ops.cpp

Lines changed: 38 additions & 24 deletions
Original file line numberDiff line numberDiff line change
@@ -2268,26 +2268,30 @@ static void aclnn_index_fill_tensor(ggml_backend_cann_context& ctx,
22682268
* stream, and persistent buffers for rope init/cache.
22692269
* @param dst The destination ggml_tensor whose computation
22702270
* depends on the RoPE values (usually Qcur/Kcur).
2271-
* @param sin_tensor_buffer Pre-allocated buffer for storing repeated sin values.
2272-
* @param cos_tensor_buffer Pre-allocated buffer for storing repeated cos values.
22732271
* @param theta_scale Scalar exponent base for computing theta scale values.
22742272
* @param freq_scale Frequency scaling factor, applied to theta scale.
22752273
* @param attn_factor Attention scaling factor, applied to sin/cos.
22762274
* @param is_neox Whether to use Neox-style repeat strategy
22772275
* (dim expansion vs repeat_interleave).
22782276
*/
22792277
static void aclnn_cache_init(ggml_backend_cann_context& ctx, ggml_tensor* dst,
2280-
void* sin_tensor_buffer, void* cos_tensor_buffer,
22812278
float* corr_dims, float ext_factor,
22822279
float theta_scale, float freq_scale,
22832280
float attn_factor, bool is_neox) {
2284-
// int sin/cos cache, cache has different repeat method depond on
2285-
// @param.is_neox
2286-
22872281
ggml_tensor* src0 = dst->src[0]; // input
22882282
ggml_tensor* src1 = dst->src[1]; // position
22892283
ggml_tensor* src2 = dst->src[2]; // freq_factors
22902284

2285+
if(src2 == nullptr && ctx.rope_cache.cached
2286+
&& ctx.rope_cache.ext_factor == ext_factor
2287+
&& ctx.rope_cache.theta_scale == theta_scale
2288+
&& ctx.rope_cache.freq_scale == freq_scale
2289+
&& ctx.rope_cache.attn_factor == attn_factor
2290+
&& ctx.rope_cache.is_neox == is_neox) {
2291+
// use cache.
2292+
return;
2293+
}
2294+
22912295
int64_t theta_scale_length = src0->ne[0] / 2;
22922296
int64_t theta_scale_ne[] = {theta_scale_length, 1, 1, 1};
22932297
size_t theta_scale_nb[] = {sizeof(float), sizeof(float), sizeof(float),
@@ -2316,8 +2320,6 @@ static void aclnn_cache_init(ggml_backend_cann_context& ctx, ggml_tensor* dst,
23162320
ctx.rope_cache.freq_scale != freq_scale) {
23172321

23182322
ctx.rope_cache.theta_scale_length = theta_scale_length;
2319-
ctx.rope_cache.theta_scale = theta_scale;
2320-
ctx.rope_cache.freq_scale = freq_scale;
23212323

23222324
if (ctx.rope_cache.theta_scale_cache != nullptr) {
23232325
ACL_CHECK(aclrtFree(ctx.rope_cache.theta_scale_cache));
@@ -2342,7 +2344,7 @@ static void aclnn_cache_init(ggml_backend_cann_context& ctx, ggml_tensor* dst,
23422344
// return MIN(1, MAX(0, y)) - 1;
23432345
yarn_ramp_allocator.alloc(theta_scale_length * sizeof(float));
23442346
void* yarn_ramp_buffer = yarn_ramp_allocator.get();
2345-
acl_yarn_ramp_tensor = ggml_cann_create_tensor(yarn_ramp_buffer, ACL_FLOAT, sizeof(float_t),
2347+
acl_yarn_ramp_tensor = ggml_cann_create_tensor(yarn_ramp_buffer, ACL_FLOAT, sizeof(float),
23462348
theta_scale_ne, theta_scale_nb, GGML_MAX_DIMS);
23472349
float zero_value = 0, one_value = 1;
23482350
float denom_safe_value = MAX(0.001f, corr_dims[1] - corr_dims[0]);
@@ -2411,6 +2413,20 @@ static void aclnn_cache_init(ggml_backend_cann_context& ctx, ggml_tensor* dst,
24112413
ggml_cann_release_resources(ctx, acl_freq_factors_tensor, acl_freq_fac_res_tensor);
24122414
}
24132415

2416+
// init sin_repeat && cos_repeat, only to accelerate first layer on each device
2417+
if (position_length > ctx.rope_cache.position_length) {
2418+
ctx.rope_cache.position_length = position_length;
2419+
if (ctx.rope_cache.sin_cache != nullptr) {
2420+
ACL_CHECK(aclrtFree(ctx.rope_cache.sin_cache));
2421+
}
2422+
if (ctx.rope_cache.cos_cache != nullptr) {
2423+
ACL_CHECK(aclrtFree(ctx.rope_cache.cos_cache));
2424+
}
2425+
int64_t repeat_theta_length = theta_scale_length * position_length * 2;
2426+
ACL_CHECK(aclrtMalloc(&ctx.rope_cache.sin_cache, repeat_theta_length * sizeof(float), ACL_MEM_MALLOC_HUGE_FIRST));
2427+
ACL_CHECK(aclrtMalloc(&ctx.rope_cache.cos_cache, repeat_theta_length * sizeof(float), ACL_MEM_MALLOC_HUGE_FIRST));
2428+
}
2429+
24142430
// position
24152431
aclTensor* acl_position_tensor = ggml_cann_create_tensor(
24162432
src1->data, ggml_cann_type_mapping(src1->type),
@@ -2462,10 +2478,10 @@ static void aclnn_cache_init(ggml_backend_cann_context& ctx, ggml_tensor* dst,
24622478
sin_reshape_nb[i] = sin_reshape_nb[i - 1] * sin_reshape_ne[i - 1];
24632479
}
24642480
aclTensor* acl_sin_repeat_tensor =
2465-
ggml_cann_create_tensor(sin_tensor_buffer, ACL_FLOAT, sizeof(float),
2481+
ggml_cann_create_tensor(ctx.rope_cache.sin_cache, ACL_FLOAT, sizeof(float),
24662482
sin_reshape_ne, sin_reshape_nb, GGML_MAX_DIMS);
24672483
aclTensor* acl_cos_repeat_tensor =
2468-
ggml_cann_create_tensor(cos_tensor_buffer, ACL_FLOAT, sizeof(float),
2484+
ggml_cann_create_tensor(ctx.rope_cache.cos_cache, ACL_FLOAT, sizeof(float),
24692485
sin_reshape_ne, sin_reshape_nb, GGML_MAX_DIMS);
24702486

24712487
// repeat
@@ -2483,6 +2499,14 @@ static void aclnn_cache_init(ggml_backend_cann_context& ctx, ggml_tensor* dst,
24832499
num_repeats, output_size);
24842500
}
24852501

2502+
// Other layers use cache except first layer.
2503+
ctx.rope_cache.cached = true;
2504+
ctx.rope_cache.ext_factor = ext_factor;
2505+
ctx.rope_cache.theta_scale = theta_scale;
2506+
ctx.rope_cache.freq_scale = freq_scale;
2507+
ctx.rope_cache.attn_factor = attn_factor;
2508+
ctx.rope_cache.is_neox = is_neox;
2509+
24862510
ggml_cann_release_resources(ctx, acl_theta_scale_tensor, acl_position_tensor,
24872511
acl_theta_tensor, acl_sin_tensor, acl_sin_repeat_tensor, acl_cos_tensor,
24882512
acl_cos_repeat_tensor);
@@ -2504,10 +2528,7 @@ aclnnStatus aclnnRotaryPositionEmbedding(void* workspace,
25042528
#endif
25052529

25062530
void ggml_cann_rope(ggml_backend_cann_context& ctx, ggml_tensor* dst) {
2507-
// TODO: use ascendc
2508-
// Only test with LLAMA model.
25092531
ggml_tensor* src0 = dst->src[0]; // input
2510-
ggml_tensor* src1 = dst->src[1];
25112532

25122533
// param
25132534
float freq_base, freq_scale, ext_factor, attn_factor, beta_fast, beta_slow;
@@ -2538,15 +2559,8 @@ void ggml_cann_rope(ggml_backend_cann_context& ctx, ggml_tensor* dst) {
25382559

25392560
const bool is_neox = mode & GGML_ROPE_TYPE_NEOX;
25402561

2541-
// sin/cos tensor length.
2542-
int64_t repeat_theta_length = src0->ne[0] * src1->ne[0];
2543-
ggml_cann_pool_alloc sin_tensor_allocator(ctx.pool(), repeat_theta_length * sizeof(float));
2544-
ggml_cann_pool_alloc cos_tensor_allocator(ctx.pool(), repeat_theta_length * sizeof(float));
2545-
void *sin_tensor_buffer = sin_tensor_allocator.get();
2546-
void *cos_tensor_buffer = cos_tensor_allocator.get();
2547-
25482562
// init ctx.rope_cos/rope_sin cache
2549-
aclnn_cache_init(ctx, dst, sin_tensor_buffer, cos_tensor_buffer, corr_dims, ext_factor,
2563+
aclnn_cache_init(ctx, dst, corr_dims, ext_factor,
25502564
theta_scale, freq_scale, attn_factor, is_neox);
25512565

25522566
int64_t sin_reshape_ne[4] = {ne00, 1, ne02, 1};
@@ -2556,10 +2570,10 @@ void ggml_cann_rope(ggml_backend_cann_context& ctx, ggml_tensor* dst) {
25562570
sin_reshape_nb[i] = sin_reshape_nb[i - 1] * sin_reshape_ne[i - 1];
25572571
}
25582572
aclTensor* acl_sin_reshape_tensor =
2559-
ggml_cann_create_tensor(sin_tensor_buffer, ACL_FLOAT, sizeof(float),
2573+
ggml_cann_create_tensor(ctx.rope_cache.sin_cache, ACL_FLOAT, sizeof(float),
25602574
sin_reshape_ne, sin_reshape_nb, GGML_MAX_DIMS);
25612575
aclTensor* acl_cos_reshape_tensor =
2562-
ggml_cann_create_tensor(cos_tensor_buffer, ACL_FLOAT, sizeof(float),
2576+
ggml_cann_create_tensor(ctx.rope_cache.cos_cache, ACL_FLOAT, sizeof(float),
25632577
sin_reshape_ne, sin_reshape_nb, GGML_MAX_DIMS);
25642578

25652579
aclTensor* acl_src = ggml_cann_create_tensor(src0);

src/ggml-cann/common.h

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -425,12 +425,27 @@ struct ggml_cann_rope_cache {
425425
if(theta_scale_cache != nullptr) {
426426
ACL_CHECK(aclrtFree(theta_scale_cache));
427427
}
428+
if(sin_cache != nullptr) {
429+
ACL_CHECK(aclrtFree(sin_cache));
430+
}
431+
if(cos_cache != nullptr) {
432+
ACL_CHECK(aclrtFree(cos_cache));
433+
}
428434
}
429435

430436
void* theta_scale_cache = nullptr;
431437
int64_t theta_scale_length = 0;
438+
// sin/cos cache, used only to accelerate first layer on each device
439+
void* sin_cache = nullptr;
440+
void* cos_cache = nullptr;
441+
int64_t position_length = 0;
442+
// Properties to check before reusing the sincos cache
443+
bool cached = false;
444+
float ext_factor = 0.0f;
432445
float theta_scale = 0.0f;
433446
float freq_scale = 0.0f;
447+
float attn_factor = 0.0f;
448+
bool is_neox = false;
434449
};
435450

436451
struct ggml_cann_tensor_cache {

src/ggml-cann/ggml-cann.cpp

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2353,6 +2353,9 @@ static enum ggml_status ggml_backend_cann_graph_compute(
23532353
ggml_cann_set_device(cann_ctx->device);
23542354
g_nz_workspaces[cann_ctx->device].clear();
23552355

2356+
// calculate rope cache for fist layer in current device.
2357+
cann_ctx->rope_cache.cached = false;
2358+
23562359
#ifdef USE_ACL_GRAPH
23572360
bool use_cann_graph = true;
23582361
bool cann_graph_update_required = false;

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