feat: timeout between token generation

- if 30 seconds pass since the last token generation abort the request
- stop the llama thread to flush any accumulated context

llm/dyn_ext_server.go

@@ -35,6 +35,7 @@ import (
 
 	"github.com/jmorganca/ollama/api"
 	"github.com/jmorganca/ollama/gpu"
+	"golang.org/x/exp/slog"
 )
 
 type dynExtServer struct {
@@ -164,6 +165,8 @@ func newDynExtServer(library, model string, adapters, projectors []string, opts
 	return llm, nil
 }
 
+var ErrPredictTimeout = fmt.Errorf("timed out waiting for next token")
+
 func (llm *dynExtServer) Predict(ctx context.Context, predict PredictOpts, fn func(PredictResult)) error {
 	resp := newExtServerResp(128)
 	defer freeExtServerResp(resp)
@@ -237,56 +240,73 @@ func (llm *dynExtServer) Predict(ctx context.Context, predict PredictOpts, fn fu
 			case <-ctx.Done():
 				return cancelCompletion(llm, resp)
 			default:
-				var result C.ext_server_task_result_t
-				C.dyn_llama_server_completion_next_result(llm.s, resp.id, &result)
-				json_resp := C.GoString(result.json_resp)
-				C.dyn_llama_server_release_task_result(llm.s, &result)
+				// this channel is used to communicate the result of each call, while allowing for a timeout
+				resultChan := make(chan C.ext_server_task_result_t)
+				// timeout waiting for a token from this specific call
+				timeout := time.After(30 * time.Second)
 
-				var p prediction
-				if err := json.Unmarshal([]byte(json_resp), &p); err != nil {
-					C.dyn_llama_server_completion_cancel(llm.s, resp.id, &resp)
-					if resp.id < 0 {
-						return fmt.Errorf("error unmarshaling llm prediction response: %w and cancel %s", err, C.GoString(resp.msg))
-					} else {
-						return fmt.Errorf("error unmarshaling llm prediction response: %w", err)
+				go func() {
+					var result C.ext_server_task_result_t
+					C.dyn_llama_server_completion_next_result(llm.s, resp.id, &result)
+					resultChan <- result
+				}()
+
+				select {
+				case result := <-resultChan:
+					json_resp := C.GoString(result.json_resp)
+					C.dyn_llama_server_release_task_result(llm.s, &result)
+
+					var p prediction
+					if err := json.Unmarshal([]byte(json_resp), &p); err != nil {
+						C.dyn_llama_server_completion_cancel(llm.s, resp.id, &resp)
+						if resp.id < 0 {
+							return fmt.Errorf("error unmarshaling llm prediction response: %w and cancel %s", err, C.GoString(resp.msg))
+						} else {
+							return fmt.Errorf("error unmarshaling llm prediction response: %w", err)
+						}
 					}
-				}
 
-				if bool(result.error) && strings.Contains(json_resp, "slot unavailable") {
-					retryNeeded = true
-					// task will already be canceled
-					break out
-				}
+					if bool(result.error) && strings.Contains(json_resp, "slot unavailable") {
+						retryNeeded = true
+						// task will already be canceled
+						break out
+					}
 
-				switch {
-				case strings.TrimSpace(p.Content) == lastToken:
-					tokenRepeat++
-				default:
-					lastToken = strings.TrimSpace(p.Content)
-					tokenRepeat = 0
-				}
+					switch {
+					case strings.TrimSpace(p.Content) == lastToken:
+						tokenRepeat++
+					default:
+						lastToken = strings.TrimSpace(p.Content)
+						tokenRepeat = 0
+					}
 
-				// 30 picked as an arbitrary max token repeat limit, modify as needed
-				if tokenRepeat > 30 {
-					slog.Debug("prediction aborted, token repeat limit reached")
-					return cancelCompletion(llm, resp)
-				}
+					// 30 picked as an arbitrary max token repeat limit, modify as needed
+					if tokenRepeat > 30 {
+						slog.Debug("prediction aborted, token repeat limit reached")
+						return cancelCompletion(llm, resp)
+					}
 
-				if p.Content != "" {
-					fn(PredictResult{
-						Content: p.Content,
-					})
-				}
+					if p.Content != "" {
+						fn(PredictResult{
+							Content: p.Content,
+						})
+					}
 
-				if p.Stop || bool(result.stop) {
-					fn(PredictResult{
-						Done:               true,
-						PromptEvalCount:    p.Timings.PromptN,
-						PromptEvalDuration: parseDurationMs(p.Timings.PromptMS),
-						EvalCount:          p.Timings.PredictedN,
-						EvalDuration:       parseDurationMs(p.Timings.PredictedMS),
-					})
-					return nil
+					if p.Stop || bool(result.stop) {
+						fn(PredictResult{
+							Done:               true,
+							PromptEvalCount:    p.Timings.PromptN,
+							PromptEvalDuration: parseDurationMs(p.Timings.PromptMS),
+							EvalCount:          p.Timings.PredictedN,
+							EvalDuration:       parseDurationMs(p.Timings.PredictedMS),
+						})
+						return nil
+					}
+				case <-timeout:
+					if err := cancelCompletion(llm, resp); err != nil {
+						slog.Error("failed to cancel completion on predict timeout: ", err)
+					}
+					return ErrPredictTimeout
 				}
 			}
 		}

server/routes.go

@@ -1362,6 +1362,15 @@ func ChatHandler(c *gin.Context) {
 			Options: opts,
 		}
 		if err := loaded.runner.Predict(c.Request.Context(), predictReq, fn); err != nil {
+			if errors.Is(err, llm.ErrPredictTimeout) {
+				// the loaded runner may be unresponsive, stop it now
+				if loaded.runner != nil {
+					loaded.runner.Close()
+				}
+				loaded.runner = nil
+				loaded.Model = nil
+				loaded.Options = nil
+			}
 			ch <- gin.H{"error": err.Error()}
 		}
 	}()