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Merged
am17an merged 4 commits into from
Feb 21, 2026
Merged

Improve CUDA graph capture #19754

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a874a2c
Improve CUDA graph capture
gaugarg-nv Feb 20, 2026
a11e550
Update ggml/src/ggml-cuda/ggml-cuda.cu
gaugarg-nv Feb 21, 2026
27b965b
Remove EM dashes
gaugarg-nv Feb 21, 2026
692ceef
Update ggml/src/ggml-cuda/ggml-cuda.cu
gaugarg-nv Feb 21, 2026
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17 changes: 2 additions & 15 deletions ggml/src/ggml-cuda/common.cuh
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Original file line number Diff line number Diff line change
Expand Up @@ -1149,8 +1149,7 @@ struct ggml_cuda_graph {
size_t num_nodes = 0;
std::vector<cudaGraphNode_t> nodes;
bool disable_due_to_gpu_arch = false;
bool disable_due_to_too_many_updates = false;
int number_consecutive_updates = 0;
bool warmup_complete = false;
std::vector<ggml_cuda_graph_node_properties> props;

// these are extra tensors (inputs) that participate in the ggml graph but are not nodes
Expand All @@ -1159,21 +1158,9 @@ struct ggml_cuda_graph {
// ref: https://github.com/ggml-org/llama.cpp/pull/19165
std::vector<ggml_cuda_graph_node_properties> extra;

void record_update(bool use_graph, bool update_required) {
if (use_graph && update_required) {
number_consecutive_updates++;
} else {
number_consecutive_updates = 0;
}
if (number_consecutive_updates >= 4) {
GGML_LOG_DEBUG("%s: disabling CUDA graphs due to too many consecutive updates\n", __func__);
disable_due_to_too_many_updates = true;
}
}

bool is_enabled() const {
static const bool disable_cuda_graphs_due_to_env = (getenv("GGML_CUDA_DISABLE_GRAPHS") != nullptr);
return !(disable_due_to_gpu_arch || disable_cuda_graphs_due_to_env || disable_due_to_too_many_updates);
return !(disable_due_to_gpu_arch || disable_cuda_graphs_due_to_env);
}
#endif
};
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35 changes: 26 additions & 9 deletions ggml/src/ggml-cuda/ggml-cuda.cu
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Expand Up @@ -2979,10 +2979,6 @@ static bool ggml_cuda_graph_update_required(ggml_backend_cuda_context * cuda_ctx
const void * graph_key = ggml_cuda_graph_get_key(cgraph);
ggml_cuda_graph * graph = cuda_ctx->cuda_graph(graph_key);

if (graph->instance == nullptr) {
res = true;
}

// Check if the graph size has changed
if (graph->props.size() != (size_t)cgraph->n_nodes) {
res = true;
Expand Down Expand Up @@ -3931,14 +3927,35 @@ static enum ggml_status ggml_backend_cuda_graph_compute(ggml_backend_t backend,
#ifdef USE_CUDA_GRAPH
graph_key = ggml_cuda_graph_get_key(cgraph);

use_cuda_graph = ggml_cuda_graph_set_enabled(cuda_ctx, graph_key);
ggml_cuda_graph_set_enabled(cuda_ctx, graph_key);

@ORippler ORippler Feb 20, 2026

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strictly speaking this function solely checks whether the GPU supports cudaGraphs, but we can change the name in a separate PR


ggml_cuda_graph * graph = cuda_ctx->cuda_graph(graph_key);
if (graph->is_enabled()) {
cuda_graph_update_required = ggml_cuda_graph_update_required(cuda_ctx, cgraph);
use_cuda_graph = ggml_cuda_graph_check_compability(cgraph);

graph->record_update(use_cuda_graph, cuda_graph_update_required);
const bool graph_compatible = ggml_cuda_graph_check_compability(cgraph);
if (graph_compatible) {
const bool properties_changed = ggml_cuda_graph_update_required(cuda_ctx, cgraph);

if (!graph->warmup_complete) {
// Warmup: need at least 2 calls with no property change on the 2nd call
if (!properties_changed) {
graph->warmup_complete = true;
GGML_LOG_DEBUG("%s: CUDA graph warmup complete\n", __func__);
use_cuda_graph = true;
cuda_graph_update_required = true;
}
// else: properties changed or first call - execute directly (use_cuda_graph stays false)
} else {
// Post-warmup: normal CUDA graph operation
if (properties_changed) {
// Properties changed - reset warmup, execute directly until stable again
graph->warmup_complete = false;
GGML_LOG_DEBUG("%s: CUDA graph warmup reset\n", __func__);
} else {
use_cuda_graph = true;
cuda_graph_update_required = graph->instance == nullptr;
}
}
}
}
#endif // USE_CUDA_GRAPH

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