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llama : add session file format and saved sessions in main (#1169)

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Evan Jones 2023-04-28 11:59:37 -04:00 • committed by GitHub
parent 11d902364b
commit 1481a9cf25
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6 changed files with 156 additions and 2 deletions
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89
examples/main/main.cpp
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@ -157,6 +157,32 @@ int main(int argc, char ** argv) {
// Add a space in front of the first character to match OG llama tokenizer behavior
params.prompt.insert(0, 1, ' ');
std::string path_session = params.path_session;
std::vector<llama_token> session_tokens;
if (!path_session.empty()) {
fprintf(stderr, "%s: attempting to load saved session from %s..\n", __func__, path_session.c_str());
// REVIEW - fopen to check for existing session
FILE * fp = std::fopen(path_session.c_str(), "rb");
if (fp != NULL) {
std::fclose(fp);
session_tokens.resize(params.n_ctx);
size_t n_token_count_out = 0;
const size_t n_session_bytes = llama_load_session_file(ctx, path_session.c_str(), session_tokens.data(), session_tokens.capacity(), &n_token_count_out);
session_tokens.resize(n_token_count_out);
if (n_session_bytes > 0) {
fprintf(stderr, "%s: loaded %zu bytes of session data!\n", __func__, n_session_bytes);
} else {
fprintf(stderr, "%s: could not load session file, will recreate\n", __func__);
}
} else {
fprintf(stderr, "%s: session file does not exist, will create\n", __func__);
}
}
// tokenize the prompt
auto embd_inp = ::llama_tokenize(ctx, params.prompt, true);
@ -167,6 +193,26 @@ int main(int argc, char ** argv) {
return 1;
}
// debug message about similarity of saved session, if applicable
size_t n_matching_session_tokens = 0;
if (session_tokens.size()) {
for (llama_token id : session_tokens) {
if (n_matching_session_tokens >= embd_inp.size() || id != embd_inp[n_matching_session_tokens]) {
break;
}
n_matching_session_tokens++;
}
if (n_matching_session_tokens >= embd_inp.size()) {
fprintf(stderr, "%s: session file has exact match for prompt!\n", __func__);
} else if (n_matching_session_tokens < (embd_inp.size() / 2)) {
fprintf(stderr, "%s: warning: session file has low similarity to prompt (%zu / %zu tokens); will mostly be reevaluated\n",
__func__, n_matching_session_tokens, embd_inp.size());
} else {
fprintf(stderr, "%s: session file matches %zu / %zu tokens of prompt\n",
__func__, n_matching_session_tokens, embd_inp.size());
}
}
// number of tokens to keep when resetting context
if (params.n_keep < 0 || params.n_keep > (int)embd_inp.size() || params.instruct) {
params.n_keep = (int)embd_inp.size();
@ -252,9 +298,16 @@ int main(int argc, char ** argv) {
bool is_antiprompt = false;
bool input_noecho = false;
// HACK - because session saving incurs a non-negligible delay, for now skip re-saving session
// if we loaded a session with at least 75% similarity. It's currently just used to speed up the
// initial prompt so it doesn't need to be an exact match.
bool need_to_save_session = !path_session.empty() && n_matching_session_tokens < (embd_inp.size() * 3 / 4);
int n_past = 0;
int n_remain = params.n_predict;
int n_consumed = 0;
int n_session_consumed = 0;
// the first thing we will do is to output the prompt, so set color accordingly
set_console_color(con_st, CONSOLE_COLOR_PROMPT);
@ -276,6 +329,9 @@ int main(int argc, char ** argv) {
// insert n_left/2 tokens at the start of embd from last_n_tokens
embd.insert(embd.begin(), last_n_tokens.begin() + n_ctx - n_left/2 - embd.size(), last_n_tokens.end() - embd.size());
// REVIEW - stop saving session if we run out of context
path_session = "";
//printf("\n---\n");
//printf("resetting: '");
//for (int i = 0; i < (int) embd.size(); i++) {
@ -285,6 +341,28 @@ int main(int argc, char ** argv) {
//printf("\n---\n");
}
// try to reuse a matching prefix from the loaded session instead of re-eval (via n_past)
// REVIEW
if (n_session_consumed < (int) session_tokens.size()) {
size_t i = 0;
for ( ; i < embd.size(); i++) {
if (embd[i] != session_tokens[n_session_consumed]) {
session_tokens.resize(n_session_consumed);
break;
}
n_past++;
n_session_consumed++;
if (n_session_consumed >= (int) session_tokens.size()) {
break;
}
}
if (i > 0) {
embd.erase(embd.begin(), embd.begin() + i);
}
}
// evaluate tokens in batches
// embd is typically prepared beforehand to fit within a batch, but not always
for (int i = 0; i < (int) embd.size(); i += params.n_batch) {
@ -298,6 +376,11 @@ int main(int argc, char ** argv) {
}
n_past += n_eval;
}
if (embd.size() > 0 && !path_session.empty()) {
session_tokens.insert(session_tokens.end(), embd.begin(), embd.end());
n_session_consumed = session_tokens.size();
}
}
embd.clear();
@ -309,6 +392,12 @@ int main(int argc, char ** argv) {
const float temp = params.temp;
const float repeat_penalty = params.repeat_penalty;
// optionally save the session on first sample (for faster prompt loading next time)
if (!path_session.empty() && need_to_save_session) {
need_to_save_session = false;
llama_save_session_file(ctx, path_session.c_str(), session_tokens.data(), session_tokens.size());
}
llama_token id = 0;
{