spec: add spec metrics mean acceptance length and acceptance rate per position (#24536)

* spec: add spec metrics mean acceptance length and acceptance per pos

* fix as suggestion

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

* fix as suggestion

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

* fix as suggestion

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

* fix as suggestions

---------

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>
This commit is contained in:
Ruixiang Wang
2026-06-16 10:23:09 +03:00
committed by GitHub
co-authored by Georgi Gerganov
parent e3a74b2990
commit 635b65ad7a
2 changed files with 57 additions and 4 deletions
+27 -3
View File
@@ -201,6 +201,8 @@ struct server_slot {
// Speculative decoding stats
int32_t n_draft_total = 0; // Total draft tokens generated
int32_t n_draft_accepted = 0; // Draft tokens actually accepted
int32_t n_draft_verif_steps = 0; // Total draft token verification steps by the target model
std::vector<int32_t> n_accepted_per_pos; // Accepted tokens per draft position
void reset() {
SLT_DBG(*this, "%s", "\n");
@@ -227,6 +229,8 @@ struct server_slot {
// clear speculative decoding stats
n_draft_total = 0;
n_draft_accepted = 0;
n_draft_verif_steps = 0;
n_accepted_per_pos.clear();
task_prev = std::move(task);
task.reset();
@@ -509,10 +513,22 @@ struct server_slot {
llama_perf_context(ctx_tgt).n_reused);
if (n_draft_total > 0) {
const float draft_ratio = (float) n_draft_accepted / n_draft_total;
const float draft_ratio = (float) n_draft_accepted / n_draft_total;
const double mean_acc_len = n_draft_verif_steps > 0 ? 1.0 + (double) n_draft_accepted / (double) n_draft_verif_steps : 1.0;
std::string acceptance_rates_per_pos;
if (n_draft_verif_steps > 0) {
for (size_t i = 0; i < n_accepted_per_pos.size(); ++i) {
if (i > 0) {
acceptance_rates_per_pos += ", ";
}
acceptance_rates_per_pos += string_format("%.3f", (double) n_accepted_per_pos[i] / (double) n_draft_verif_steps);
}
}
SLT_INF(*this,
"draft acceptance = %0.5f (%5d accepted / %5d generated)\n",
draft_ratio, n_draft_accepted, n_draft_total);
"draft acceptance = %0.5f (%5d accepted / %5d generated), mean acceptance length = %5.2f, acceptance rate per position = (%s)\n",
draft_ratio, n_draft_accepted, n_draft_total, mean_acc_len, acceptance_rates_per_pos.c_str());
}
common_speculative_print_stats(spec);
@@ -3543,6 +3559,14 @@ private:
// update how many tokens out of those tested were accepted
slot.n_draft_accepted += ids.size() - 1;
slot.n_draft_verif_steps += 1;
if (slot.n_accepted_per_pos.empty()) {
slot.n_accepted_per_pos.resize(common_speculative_n_max(&params_base.speculative), 0);
}
for (size_t i = 0; i < ids.size() - 1 && i < slot.n_accepted_per_pos.size(); ++i) {
slot.n_accepted_per_pos[i]++;
}
// add accepted tokens to the prompt
slot.prompt.tokens.keep_first(slot.prompt.n_tokens() - n_draft);