sched.go 27.4 KB
Newer Older
Daniel Hiltgen's avatar
Daniel Hiltgen committed
1
2
3
4
5
6
7
8
package server

import (
	"context"
	"errors"
	"fmt"
	"log/slog"
	"reflect"
9
	"runtime"
Daniel Hiltgen's avatar
Daniel Hiltgen committed
10
11
12
13
14
15
	"sort"
	"strings"
	"sync"
	"time"

	"github.com/ollama/ollama/api"
16
	"github.com/ollama/ollama/envconfig"
Daniel Hiltgen's avatar
Daniel Hiltgen committed
17
18
19
20
21
22
23
24
25
	"github.com/ollama/ollama/format"
	"github.com/ollama/ollama/gpu"
	"github.com/ollama/ollama/llm"
)

type LlmRequest struct {
	ctx             context.Context //nolint:containedctx
	model           *Model
	opts            api.Options
Daniel Hiltgen's avatar
Daniel Hiltgen committed
26
	origNumCtx      int // Track the initial ctx request
27
	sessionDuration *api.Duration
Daniel Hiltgen's avatar
Daniel Hiltgen committed
28
29
	successCh       chan *runnerRef
	errCh           chan error
30
	schedAttempts   uint
Daniel Hiltgen's avatar
Daniel Hiltgen committed
31
32
33
34
35
36
37
38
39
40
41
}

type Scheduler struct {
	pendingReqCh  chan *LlmRequest
	finishedReqCh chan *LlmRequest
	expiredCh     chan *runnerRef
	unloadedCh    chan interface{}

	loaded   map[string]*runnerRef
	loadedMu sync.Mutex

Daniel Hiltgen's avatar
Daniel Hiltgen committed
42
43
	loadFn       func(req *LlmRequest, ggml *llm.GGML, gpus gpu.GpuInfoList, numParallel int)
	newServerFn  func(gpus gpu.GpuInfoList, model string, ggml *llm.GGML, adapters []string, projectors []string, opts api.Options, numParallel int) (llm.LlamaServer, error)
44
45
46
	getGpuFn     func() gpu.GpuInfoList
	getCpuFn     func() gpu.GpuInfoList
	reschedDelay time.Duration
Daniel Hiltgen's avatar
Daniel Hiltgen committed
47
48
}

49
50
51
52
53
54
55
56
57
58
// Default automatic value for number of models we allow per GPU
// Model will still need to fit in VRAM, but loading many small models
// on a large GPU can cause stalling
var defaultModelsPerGPU = 3

// Default automatic value for parallel setting
// Model will still need to fit in VRAM.  If this setting wont fit
// we'll back off down to 1 to try to get it to fit
var defaultParallel = 4

59
var ErrMaxQueue = fmt.Errorf("server busy, please try again.  maximum pending requests exceeded")
Daniel Hiltgen's avatar
Daniel Hiltgen committed
60
61
62

func InitScheduler(ctx context.Context) *Scheduler {
	sched := &Scheduler{
63
64
65
66
		pendingReqCh:  make(chan *LlmRequest, envconfig.MaxQueuedRequests),
		finishedReqCh: make(chan *LlmRequest, envconfig.MaxQueuedRequests),
		expiredCh:     make(chan *runnerRef, envconfig.MaxQueuedRequests),
		unloadedCh:    make(chan interface{}, envconfig.MaxQueuedRequests),
Daniel Hiltgen's avatar
Daniel Hiltgen committed
67
68
69
		loaded:        make(map[string]*runnerRef),
		newServerFn:   llm.NewLlamaServer,
		getGpuFn:      gpu.GetGPUInfo,
70
		getCpuFn:      gpu.GetCPUInfo,
71
		reschedDelay:  250 * time.Millisecond,
Daniel Hiltgen's avatar
Daniel Hiltgen committed
72
73
74
75
76
77
	}
	sched.loadFn = sched.load
	return sched
}

// context must be canceled to decrement ref count and release the runner
78
func (s *Scheduler) GetRunner(c context.Context, model *Model, opts api.Options, sessionDuration *api.Duration) (chan *runnerRef, chan error) {
79
80
81
82
	if opts.NumCtx < 4 {
		opts.NumCtx = 4
	}

Daniel Hiltgen's avatar
Daniel Hiltgen committed
83
84
85
86
87
88
89
90
	req := &LlmRequest{
		ctx:             c,
		model:           model,
		opts:            opts,
		sessionDuration: sessionDuration,
		successCh:       make(chan *runnerRef),
		errCh:           make(chan error, 1),
	}
91

Daniel Hiltgen's avatar
Daniel Hiltgen committed
92
93
94
	select {
	case s.pendingReqCh <- req:
	default:
95
		req.errCh <- ErrMaxQueue
Daniel Hiltgen's avatar
Daniel Hiltgen committed
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
	}
	return req.successCh, req.errCh
}

// Returns immediately, spawns go routines for the scheduler which will shutdown when ctx is done
func (s *Scheduler) Run(ctx context.Context) {
	slog.Debug("starting llm scheduler")
	go func() {
		s.processPending(ctx)
	}()

	go func() {
		s.processCompleted(ctx)
	}()
}

func (s *Scheduler) processPending(ctx context.Context) {
	for {
		select {
		case <-ctx.Done():
			slog.Debug("shutting down scheduler pending loop")
			return
		case pending := <-s.pendingReqCh:
			// Block other requests until we get this pending request running
120
			pending.schedAttempts++
Daniel Hiltgen's avatar
Daniel Hiltgen committed
121
122
			if pending.origNumCtx == 0 {
				pending.origNumCtx = pending.opts.NumCtx
Daniel Hiltgen's avatar
Daniel Hiltgen committed
123
			}
124
125
126
127
128

			if pending.ctx.Err() != nil {
				slog.Debug("pending request cancelled or timed out, skipping scheduling")
				continue
			}
Daniel Hiltgen's avatar
Daniel Hiltgen committed
129
130
131
132
133
134
135
			numParallel := envconfig.NumParallel
			// TODO (jmorganca): multimodal models don't support parallel yet
			// see https://github.com/ollama/ollama/issues/4165
			if len(pending.model.ProjectorPaths) > 0 && numParallel != 1 {
				numParallel = 1
				slog.Warn("multimodal models don't support parallel requests yet")
			}
136

Daniel Hiltgen's avatar
Daniel Hiltgen committed
137
138
139
140
141
142
143
144
145
146
147
148
149
150
			for {
				var runnerToExpire *runnerRef
				s.loadedMu.Lock()
				runner := s.loaded[pending.model.ModelPath]
				loadedCount := len(s.loaded)
				s.loadedMu.Unlock()
				if runner != nil {
					if runner.needsReload(ctx, pending) {
						runnerToExpire = runner
					} else {
						// Runner is usable, return it
						pending.useLoadedRunner(runner, s.finishedReqCh)
						break
					}
151
				} else if envconfig.MaxRunners > 0 && loadedCount >= envconfig.MaxRunners {
Daniel Hiltgen's avatar
Daniel Hiltgen committed
152
					slog.Debug("max runners achieved, unloading one to make room", "runner_count", loadedCount)
153
					runnerToExpire = s.findRunnerToUnload()
Daniel Hiltgen's avatar
Daniel Hiltgen committed
154
				} else {
155
					// Either no models are loaded or below envconfig.MaxRunners
Daniel Hiltgen's avatar
Daniel Hiltgen committed
156
					// Get a refreshed GPU list
157
158
159
160
161
162
					var gpus gpu.GpuInfoList
					if pending.opts.NumGPU == 0 {
						gpus = s.getCpuFn()
					} else {
						gpus = s.getGpuFn()
					}
163

164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
					if envconfig.MaxRunners <= 0 {
						// No user specified MaxRunners, so figure out what automatic setting to use
						// If all GPUs have reliable free memory reporting, defaultModelsPerGPU * the number of GPUs
						// if any GPU has unreliable free memory reporting, 1x the number of GPUs
						allReliable := true
						for _, gpu := range gpus {
							if gpu.UnreliableFreeMemory {
								allReliable = false
								break
							}
						}
						if allReliable {
							envconfig.MaxRunners = defaultModelsPerGPU * len(gpus)
							slog.Debug("updating default concurrency", "OLLAMA_MAX_LOADED_MODELS", envconfig.MaxRunners, "gpu_count", len(gpus))
						} else {
							slog.Info("one or more GPUs detected that are unable to accurately report free memory - disabling default concurrency")
							envconfig.MaxRunners = len(gpus)
						}
					}
183

184
					// Load model for fitting
185
					ggml, err := llm.LoadModel(pending.model.ModelPath, 0)
186
187
188
189
					if err != nil {
						pending.errCh <- err
						break
					}
190

191
192
					// Evaluate if the model will fit in the available system memory, or if we should unload a model first
					if len(gpus) == 1 && gpus[0].Library == "cpu" {
Daniel Hiltgen's avatar
Daniel Hiltgen committed
193
194
195
196
197
						// simplifying assumption of defaultParallel when in CPU mode
						if numParallel <= 0 {
							numParallel = defaultParallel
						}

198
199
						pending.opts.NumCtx = pending.origNumCtx * numParallel

200
201
						if loadedCount == 0 {
							slog.Debug("cpu mode with first model, loading")
Daniel Hiltgen's avatar
Daniel Hiltgen committed
202
							s.loadFn(pending, ggml, gpus, numParallel)
203
204
205
206
207
							break
						}
						runnerToExpire = s.maybeFindCPURunnerToUnload(pending, ggml, gpus)
						if runnerToExpire == nil {
							slog.Debug("cpu mode with available system memory or first model, loading")
Daniel Hiltgen's avatar
Daniel Hiltgen committed
208
							s.loadFn(pending, ggml, gpus, numParallel)
209
210
211
212
213
							break
						}
						// else we need to expire a runner
					} else if loadedCount == 0 {
						// No models loaded. Load the model but prefer the best fit.
214
						slog.Debug("loading first model", "model", pending.model.ModelPath)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
215
						g := pickBestFitGPUs(pending, ggml, gpus, &numParallel)
216
217
218
						if g != nil {
							gpus = g
						}
Daniel Hiltgen's avatar
Daniel Hiltgen committed
219
						s.loadFn(pending, ggml, gpus, numParallel)
220
221
222
						break
					}

223
					if runnerToExpire == nil {
224
225
226
227
228
229
						// More than one loaded model, so we have to see if the
						// new one fits
						//
						// We want to avoid loading on any GPUs that have other
						// models still loading on them to avoid potential races
						// with VRAM consumption ramping up during load
Daniel Hiltgen's avatar
Daniel Hiltgen committed
230
						availGpus := s.filterGPUsWithoutLoadingModels(gpus)
231

232
						// Update free memory from currently loaded models
233
						s.updateFreeSpace(availGpus)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
234
						fitGpus := pickBestFitGPUs(pending, ggml, availGpus, &numParallel)
235
						if fitGpus != nil {
236
							slog.Debug("new model fits with existing models, loading")
Daniel Hiltgen's avatar
Daniel Hiltgen committed
237
							s.loadFn(pending, ggml, fitGpus, numParallel)
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
							break
						}

						// We couldn't find a set of GPUs to fully load the new
						// model. If no other models are loading (both GPU lists
						// are the same) then we need to unload another model to
						// make room
						if len(availGpus) < len(gpus) {
							// There are other requests pending, and this one
							// needs more time, so put it on the back of the
							// queue so that we might satisfy other pending
							// requests that aren't blocked
							go func() {
								// Process in a go routine to avoid deadlocking
								// the scheduler if our queue is full
								slog.Debug("delaying scheduling while other models finish loading", "attempts", pending.schedAttempts, "model", pending.model.ModelPath)
								time.Sleep(s.reschedDelay)
								s.pendingReqCh <- pending
							}()
257
258
259
							break
						}
						runnerToExpire = s.findRunnerToUnload()
Daniel Hiltgen's avatar
Daniel Hiltgen committed
260
261
262
263
264
265
266
267
268
269
					}
				}

				if runnerToExpire == nil {
					// Shouildn't happen
					slog.Error("runner to expire was nil!")
					continue
				}
				// Trigger an expiration to unload once it's done
				runnerToExpire.refMu.Lock()
270
				slog.Debug("resetting model to expire immediately to make room", "modelPath", runnerToExpire.modelPath, "refCount", runnerToExpire.refCount)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
271
272
273
274
275
276
277
278
279
280
281
282
				if runnerToExpire.expireTimer != nil {
					runnerToExpire.expireTimer.Stop()
					runnerToExpire.expireTimer = nil
				}
				runnerToExpire.sessionDuration = 0
				if runnerToExpire.refCount <= 0 {
					s.expiredCh <- runnerToExpire
				}
				runnerToExpire.refMu.Unlock()
				// Wait for the unload to happen
				// Note: at this point we're queueing up all incoming requests, even if they were for
				// a different model that's loaded and not scheduled to be removed.
283
				slog.Debug("waiting for pending requests to complete and unload to occur", "modelPath", runnerToExpire.modelPath)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
284
285
286
287
288
				select {
				case <-ctx.Done():
					slog.Debug("shutting down scheduler pending loop")
					return
				case <-s.unloadedCh:
289
					slog.Debug("unload completed", "modelPath", runnerToExpire.modelPath)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
					continue
				}
			}
		case <-s.unloadedCh:
			// An unload request when there are no pending request can be ignored
			slog.Debug("ignoring unload event with no pending requests")
		}
	}
}

func (s *Scheduler) processCompleted(ctx context.Context) {
	// Process completed requests, expired timers, and unloading models
	for {
		select {
		case <-ctx.Done():
			slog.Debug("shutting down scheduler completed loop")
			return
		case finished := <-s.finishedReqCh:
			s.loadedMu.Lock()
			runner := s.loaded[finished.model.ModelPath]
			s.loadedMu.Unlock()
			if runner == nil {
312
				slog.Error("finished request signal received after model unloaded", "modelPath", finished.model.ModelPath)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
313
314
315
316
317
318
				continue
			}
			runner.refMu.Lock()
			runner.refCount--
			if runner.refCount <= 0 {
				if runner.sessionDuration <= 0 {
319
					slog.Debug("runner with zero duration has gone idle, expiring to unload", "modelPath", runner.modelPath)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
320
321
322
323
324
325
					if runner.expireTimer != nil {
						runner.expireTimer.Stop()
						runner.expireTimer = nil
					}
					s.expiredCh <- runner
				} else if runner.expireTimer == nil {
326
					slog.Debug("runner with non-zero duration has gone idle, adding timer", "modelPath", runner.modelPath, "duration", runner.sessionDuration)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
327
					runner.expireTimer = time.AfterFunc(runner.sessionDuration, func() {
328
						slog.Debug("timer expired, expiring to unload", "modelPath", runner.modelPath)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
329
330
331
332
						runner.refMu.Lock()
						defer runner.refMu.Unlock()
						if runner.expireTimer != nil {
							runner.expireTimer.Stop()
333
							runner.expireTimer = nil
Daniel Hiltgen's avatar
Daniel Hiltgen committed
334
335
336
						}
						s.expiredCh <- runner
					})
337
					runner.expiresAt = time.Now().Add(runner.sessionDuration)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
338
				} else {
339
					slog.Debug("runner with non-zero duration has gone idle, resetting timer", "modelPath", runner.modelPath, "duration", runner.sessionDuration)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
340
					runner.expireTimer.Reset(runner.sessionDuration)
341
					runner.expiresAt = time.Now().Add(runner.sessionDuration)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
342
343
				}
			}
344
			slog.Debug("after processing request finished event", "modelPath", runner.modelPath, "refCount", runner.refCount)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
345
346
			runner.refMu.Unlock()
		case runner := <-s.expiredCh:
347
			slog.Debug("runner expired event received", "modelPath", runner.modelPath)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
348
349
350
			runner.refMu.Lock()
			if runner.refCount > 0 {
				// Shouldn't happen, but safeguard to ensure no leaked runners
351
				slog.Debug("expired event with positive ref count, retrying", "modelPath", runner.modelPath, "refCount", runner.refCount)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
352
353
354
355
356
357
358
359
360
361
				go func(runner *runnerRef) {
					// We can't unload yet, but want to as soon as the current request completes
					// So queue up another expired event
					time.Sleep(10 * time.Millisecond)
					s.expiredCh <- runner
				}(runner)
				runner.refMu.Unlock()
				continue
			}

362
			s.loadedMu.Lock()
363
			slog.Debug("got lock to unload", "modelPath", runner.modelPath)
364
			finished := runner.waitForVRAMRecovery()
Daniel Hiltgen's avatar
Daniel Hiltgen committed
365
			runner.unload()
366
			delete(s.loaded, runner.modelPath)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
367
			s.loadedMu.Unlock()
368
			slog.Debug("runner released", "modelPath", runner.modelPath)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
369
			runner.refMu.Unlock()
370
371

			<-finished
372
			slog.Debug("sending an unloaded event", "modelPath", runner.modelPath)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
373
374
375
376
377
378
379
380
381
382
383
384
			s.unloadedCh <- struct{}{}
		}
	}
}

// Complete the pending request and send the runner back to the requester
// Wires up a finished event after the request context is completed
// Updates session duration, and resets expiration timer
func (pending *LlmRequest) useLoadedRunner(runner *runnerRef, finished chan *LlmRequest) {
	runner.refMu.Lock()
	defer runner.refMu.Unlock()
	runner.refCount++
385
386
387
388
	if runner.expireTimer != nil {
		runner.expireTimer.Stop()
		runner.expireTimer = nil
	}
389
390
391
	if pending.sessionDuration != nil {
		runner.sessionDuration = pending.sessionDuration.Duration
	}
Daniel Hiltgen's avatar
Daniel Hiltgen committed
392
393
394
395
396
397
398
399
	pending.successCh <- runner
	go func() {
		<-pending.ctx.Done()
		slog.Debug("context for request finished")
		finished <- pending
	}()
}

Daniel Hiltgen's avatar
Daniel Hiltgen committed
400
401
402
403
func (s *Scheduler) load(req *LlmRequest, ggml *llm.GGML, gpus gpu.GpuInfoList, numParallel int) {
	if numParallel < 1 {
		numParallel = 1
	}
Michael Yang's avatar
Michael Yang committed
404
	sessionDuration := envconfig.KeepAlive()
405
406
407
	if req.sessionDuration != nil {
		sessionDuration = req.sessionDuration.Duration
	}
Daniel Hiltgen's avatar
Daniel Hiltgen committed
408
	llama, err := s.newServerFn(gpus, req.model.ModelPath, ggml, req.model.AdapterPaths, req.model.ProjectorPaths, req.opts, numParallel)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
409
410
411
412
413
414
415
416
417
418
419
	if err != nil {
		// some older models are not compatible with newer versions of llama.cpp
		// show a generalized compatibility error until there is a better way to
		// check for model compatibility
		if errors.Is(llm.ErrUnsupportedFormat, err) || strings.Contains(err.Error(), "failed to load model") {
			err = fmt.Errorf("%v: this model may be incompatible with your version of Ollama. If you previously pulled this model, try updating it by running `ollama pull %s`", err, req.model.ShortName)
		}
		slog.Info("NewLlamaServer failed", "model", req.model.ModelPath, "error", err)
		req.errCh <- err
		return
	}
420
421
422
423
424
	runner := &runnerRef{
		model:           req.model,
		modelPath:       req.model.ModelPath,
		llama:           llama,
		Options:         &req.opts,
425
		sessionDuration: sessionDuration,
426
427
428
429
430
431
		gpus:            gpus,
		estimatedVRAM:   llama.EstimatedVRAM(),
		estimatedTotal:  llama.EstimatedTotal(),
		loading:         true,
		refCount:        1,
	}
Daniel Hiltgen's avatar
Daniel Hiltgen committed
432
	runner.numParallel = numParallel
Daniel Hiltgen's avatar
Daniel Hiltgen committed
433
	runner.refMu.Lock()
434

Daniel Hiltgen's avatar
Daniel Hiltgen committed
435
436
437
438
439
440
441
442
443
444
445
	s.loadedMu.Lock()
	s.loaded[req.model.ModelPath] = runner
	slog.Info("loaded runners", "count", len(s.loaded))
	s.loadedMu.Unlock()

	go func() {
		defer runner.refMu.Unlock()
		if err = llama.WaitUntilRunning(req.ctx); err != nil {
			slog.Error("error loading llama server", "error", err)
			runner.refCount--
			req.errCh <- err
446
			slog.Debug("triggering expiration for failed load", "model", runner.modelPath)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
			s.expiredCh <- runner
			return
		}
		slog.Debug("finished setting up runner", "model", req.model.ModelPath)
		runner.loading = false
		go func() {
			<-req.ctx.Done()
			slog.Debug("context for request finished")
			s.finishedReqCh <- req
		}()
		req.successCh <- runner
	}()
}

func (s *Scheduler) updateFreeSpace(allGpus gpu.GpuInfoList) {
	type predKey struct {
		Library string
		ID      string
	}
	predMap := map[predKey]uint64{} // Sum up the total predicted usage per GPU for all runners
	s.loadedMu.Lock()
	for _, r := range s.loaded {
		r.refMu.Lock()
		if r.llama != nil {
			for _, gpu := range allGpus {
Daniel Hiltgen's avatar
Daniel Hiltgen committed
472
				predMap[predKey{gpu.Library, gpu.ID}] += r.llama.EstimatedVRAMByGPU(gpu.ID)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
			}
		} else {
			slog.Warn("unexpected nil runner reference, memory prediction may be incorrect")
		}
		r.refMu.Unlock()
	}
	s.loadedMu.Unlock()

	// Now that we've summed up all the GPU usage predictions across all the loaded runners, update the gpu list
	for i := range allGpus {
		if p, ok := predMap[predKey{allGpus[i].Library, allGpus[i].ID}]; ok {
			slog.Debug("gpu reported", "gpu", allGpus[i].ID, "library", allGpus[i].Library, "available", format.HumanBytes2(allGpus[i].FreeMemory))
			if p > allGpus[i].TotalMemory {
				// Shouldn't happen
				slog.Warn("predicted usage exceeds VRAM", "gpu", allGpus[i].ID, "totalMemory", allGpus[i].TotalMemory, "predicted", p)
				allGpus[i].FreeMemory = 0
			} else if (allGpus[i].TotalMemory - p) < allGpus[i].FreeMemory { // predicted free is smaller than reported free, use it
				// TODO maybe we should just always trust our numbers, since cuda's free memory reporting is laggy
				// and we might unload models we didn't actually need to.  The risk is if some other GPU intensive app is loaded
				// after we start our first runner, then we'll never acount for that, so picking the smallest free value seems prudent.
				allGpus[i].FreeMemory = allGpus[i].TotalMemory - p
			}
495
496
497
498
499
500
501
502
503
			slog.Info("updated VRAM based on existing loaded models", "gpu", allGpus[i].ID, "library", allGpus[i].Library, "total", format.HumanBytes2(allGpus[i].TotalMemory), "available", format.HumanBytes2(allGpus[i].FreeMemory))
		}
	}
}

// While models are loading the VRAM consumption numbers will be indeterminate, so we have
// to avoid scheduling another model on the same GPU(s) that haven't stabilized.
// This routine returns the set of GPUs that do not have an active loading model.
// If all GPUs have loading models, an empty list will be returned (not a single CPU entry)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
504
func (s *Scheduler) filterGPUsWithoutLoadingModels(allGpus gpu.GpuInfoList) gpu.GpuInfoList {
505
506
507
508
509
510
511
512
513
514
515
516
517
518
	ret := append(gpu.GpuInfoList{}, allGpus...)
	s.loadedMu.Lock()
	defer s.loadedMu.Unlock()
	for _, runner := range s.loaded {
		if runner.loading {
			slog.Debug("overlapping loads detected", "gpus", runner.gpus, "model", runner.modelPath)
			for _, busyGPU := range runner.gpus {
				for i := range ret {
					if ret[i].ID == busyGPU.ID {
						ret = append(ret[:i], ret[i+1:]...)
						break
					}
				}
			}
Daniel Hiltgen's avatar
Daniel Hiltgen committed
519
520
		}
	}
521
	return ret
Daniel Hiltgen's avatar
Daniel Hiltgen committed
522
523
}

524
// TODO consolidate sched_types.go
Daniel Hiltgen's avatar
Daniel Hiltgen committed
525
526
527
528
529
530
type runnerRef struct {
	refMu sync.Mutex
	// refCond   sync.Cond // Signaled on transition from 1 -> 0 refCount
	refCount uint // prevent unloading if > 0
	// unloading bool      // set to true when we are trying to unload the runner

531
532
533
534
535
	llama          llm.LlamaServer
	loading        bool            // True only during initial load, then false forever
	gpus           gpu.GpuInfoList // Recorded at time of provisioning
	estimatedVRAM  uint64
	estimatedTotal uint64
Daniel Hiltgen's avatar
Daniel Hiltgen committed
536
537
538

	sessionDuration time.Duration
	expireTimer     *time.Timer
539
	expiresAt       time.Time
Daniel Hiltgen's avatar
Daniel Hiltgen committed
540

Daniel Hiltgen's avatar
Daniel Hiltgen committed
541
542
543
	model       *Model
	modelPath   string
	numParallel int
Daniel Hiltgen's avatar
Daniel Hiltgen committed
544
545
546
547
548
	*api.Options
}

// The refMu must already be held when calling unload
func (runner *runnerRef) unload() {
549
550
551
552
	if runner.expireTimer != nil {
		runner.expireTimer.Stop()
		runner.expireTimer = nil
	}
Daniel Hiltgen's avatar
Daniel Hiltgen committed
553
554
555
	if runner.llama != nil {
		runner.llama.Close()
	}
556
	runner.model = nil
Daniel Hiltgen's avatar
Daniel Hiltgen committed
557
558
559
560
561
562
563
564
565
	runner.llama = nil
	runner.Options = nil
	runner.gpus = nil
}

func (runner *runnerRef) needsReload(ctx context.Context, req *LlmRequest) bool {
	slog.Debug("evaluating already loaded", "model", req.model.ModelPath)
	runner.refMu.Lock()
	defer runner.refMu.Unlock()
566

Daniel Hiltgen's avatar
Daniel Hiltgen committed
567
568
569
570
	timeout := 10 * time.Second
	if runner.loading {
		timeout = 2 * time.Minute // Initial load can take a long time for big models on slow systems...
	}
571

572
573
574
575
	if runner.Options == nil {
		return true
	}

576
577
578
579
580
581
582
583
	// Don't reload runner if num_gpu=-1 was provided
	optsExisting := runner.Options.Runner
	optsNew := req.opts.Runner
	if optsNew.NumGPU < 0 {
		optsExisting.NumGPU = -1
		optsNew.NumGPU = -1
	}

Daniel Hiltgen's avatar
Daniel Hiltgen committed
584
585
586
	// Normalize the NumCtx for parallelism
	optsExisting.NumCtx = optsExisting.NumCtx / runner.numParallel

587
	ctx, cancel := context.WithTimeout(ctx, timeout)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
588
	defer cancel()
589
590
	if !reflect.DeepEqual(runner.model.AdapterPaths, req.model.AdapterPaths) || // have the adapters changed?
		!reflect.DeepEqual(runner.model.ProjectorPaths, req.model.ProjectorPaths) || // have the projectors changed?
Daniel Hiltgen's avatar
Daniel Hiltgen committed
591
592
593
594
		!reflect.DeepEqual(optsExisting, optsNew) || // have the runner options changed?
		runner.llama.Ping(ctx) != nil {
		return true
	}
595

Daniel Hiltgen's avatar
Daniel Hiltgen committed
596
597
598
	return false
}

599
600
601
602
603
604
605
606
607
608
609
// Free memory reporting on GPUs can lag for a while even after the runner
// exits, so we have to keep checking until we see the available memory recover,
// otherwise subsequent model loads will get far less layers loaded or worse
// case, may completely fall back to CPU mode.
// This routine must be called before the runner unloads so it can establish
// a before and after GPU memory allocation.  The returned channel
// will be notified when we're done waiting, or have timed out and should
// proceed anyway
func (runner *runnerRef) waitForVRAMRecovery() chan interface{} {
	finished := make(chan interface{}, 1)

610
611
	// CPU or Metal don't need checking, so no waiting required
	// windows can page VRAM, only cuda currently can report accurate used vram usage
612
613
	if len(runner.gpus) == 0 ||
		(len(runner.gpus) == 1 && (runner.gpus[0].Library == "cpu" || runner.gpus[0].Library == "metal")) ||
614
		(runtime.GOOS == "windows" && runner.gpus[0].Library != "cuda") {
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
		finished <- struct{}{}
		return finished
	}
	start := time.Now()

	// Establish a baseline before we unload
	gpusBefore := gpu.GetGPUInfo()
	var totalMemoryBefore, freeMemoryBefore uint64
	for _, gpu := range gpusBefore {
		totalMemoryBefore += gpu.TotalMemory
		freeMemoryBefore += gpu.FreeMemory
	}
	go func() {
		expiresAt := start.Add(5 * time.Second) // typical convergence is 0.5-1.5s
		ticker := time.NewTicker(250 * time.Millisecond)
		defer ticker.Stop()
		for {
			<-ticker.C
			if time.Now().After(expiresAt) {
634
				slog.Warn("gpu VRAM usage didn't recover within timeout", "seconds", time.Since(start).Seconds(), "model", runner.modelPath)
635
636
637
638
639
640
641
642
643
644
645
646
				finished <- struct{}{}
			}

			// Query GPUs, look for free to go back up
			gpusNow := gpu.GetGPUInfo()
			var totalMemoryNow, freeMemoryNow uint64
			for _, gpu := range gpusNow {
				totalMemoryNow += gpu.TotalMemory
				freeMemoryNow += gpu.FreeMemory
			}
			// If we're within ~80% of the estimated memory usage recovered, bail out
			if float32(freeMemoryNow-freeMemoryBefore) > float32(runner.estimatedVRAM)*0.8 {
647
				slog.Debug(fmt.Sprintf("gpu VRAM free memory converged after %0.2f seconds", time.Since(start).Seconds()), "model", runner.modelPath)
648
649
650
651
652
653
654
655
				finished <- struct{}{}
				return
			}
		}
	}()
	return finished
}

Daniel Hiltgen's avatar
Daniel Hiltgen committed
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
type ByDuration []*runnerRef

func (a ByDuration) Len() int      { return len(a) }
func (a ByDuration) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
func (a ByDuration) Less(i, j int) bool {
	// uint64 to turn negative time (never unload) to largest
	return uint64(a[i].sessionDuration) < uint64(a[j].sessionDuration)
}

// TODO - future consideration to pick runners based on size
// type BySize []*runnerRef
// func (a BySize) Len() int           { return len(a) }
// func (a BySize) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
// func (a BySize) Less(i, j int) bool { return a[i].estimatedVRAM < a[j].estimatedVRAM }

// pickBestFitGPUs will try to find the optimal placement of the model in the available GPUs where the model fully fits
// If the model can not be fit fully within the available GPU(s) nil is returned
Daniel Hiltgen's avatar
Daniel Hiltgen committed
673
674
675
// If numParallel is <= 0, this will attempt try to optimize parallism based on available VRAM, and adjust
// opts.NumCtx accordingly
func pickBestFitGPUs(req *LlmRequest, ggml *llm.GGML, gpus gpu.GpuInfoList, numParallel *int) gpu.GpuInfoList {
Daniel Hiltgen's avatar
Daniel Hiltgen committed
676
	var estimatedVRAM uint64
Daniel Hiltgen's avatar
Daniel Hiltgen committed
677
678
679
680

	var numParallelToTry []int
	if *numParallel <= 0 {
		// If no specific parallel setting was provided, try larger then smaller, always end with 1
681
		numParallelToTry = append(numParallelToTry, defaultParallel, 1)
Daniel Hiltgen's avatar
Daniel Hiltgen committed
682
683
684
685
	} else {
		numParallelToTry = []int{*numParallel}
	}

Daniel Hiltgen's avatar
Daniel Hiltgen committed
686
687
688
689
690
	for _, gl := range gpus.ByLibrary() {
		var ok bool
		sgl := append(make(gpu.GpuInfoList, 0, len(gl)), gl...)

		// TODO - potentially sort by performance capability, existing models loaded, etc.
Daniel Hiltgen's avatar
Daniel Hiltgen committed
691
		// TODO - Eliminate any GPUs that already have envconfig.MaxRunners loaded on them
Daniel Hiltgen's avatar
Daniel Hiltgen committed
692
693
694
695
		// Note: at present, this will favor more VRAM over faster GPU speed in mixed setups
		sort.Sort(sort.Reverse(gpu.ByFreeMemory(sgl)))

		// First attempt to fit the model into a single GPU
Daniel Hiltgen's avatar
Daniel Hiltgen committed
696
		for _, p := range numParallelToTry {
Daniel Hiltgen's avatar
Daniel Hiltgen committed
697
			req.opts.NumCtx = req.origNumCtx * p
Michael Yang's avatar
bool  
Michael Yang committed
698
			if !envconfig.SchedSpread() {
Daniel Hiltgen's avatar
Daniel Hiltgen committed
699
700
701
702
703
704
				for _, g := range sgl {
					if ok, estimatedVRAM = llm.PredictServerFit([]gpu.GpuInfo{g}, ggml, req.model.AdapterPaths, req.model.ProjectorPaths, req.opts); ok {
						slog.Info("new model will fit in available VRAM in single GPU, loading", "model", req.model.ModelPath, "gpu", g.ID, "parallel", p, "available", g.FreeMemory, "required", format.HumanBytes2(estimatedVRAM))
						*numParallel = p
						return []gpu.GpuInfo{g}
					}
705
				}
Daniel Hiltgen's avatar
Daniel Hiltgen committed
706
707
708
709
710
711
712
713
			}
		}

		// TODO future refinements
		// - if multiple Libraries, see if any single GPU in any Library will fit
		// - try subsets of GPUs instead of just falling back to 1 or all in a family

		// Now try all the GPUs
Daniel Hiltgen's avatar
Daniel Hiltgen committed
714
		for _, p := range numParallelToTry {
Daniel Hiltgen's avatar
Daniel Hiltgen committed
715
			req.opts.NumCtx = req.origNumCtx * p
Daniel Hiltgen's avatar
Daniel Hiltgen committed
716
717
718
719
720
			if ok, estimatedVRAM = llm.PredictServerFit(sgl, ggml, req.model.AdapterPaths, req.model.ProjectorPaths, req.opts); ok {
				slog.Info("new model will fit in available VRAM, loading", "model", req.model.ModelPath, "library", sgl[0].Library, "parallel", p, "required", format.HumanBytes2(estimatedVRAM))
				*numParallel = p
				return sgl
			}
Daniel Hiltgen's avatar
Daniel Hiltgen committed
721
722
723
724
725
726
		}
	}
	return nil
}

// findRunnerToUnload finds a runner to unload to make room for a new model
727
func (s *Scheduler) findRunnerToUnload() *runnerRef {
Daniel Hiltgen's avatar
Daniel Hiltgen committed
728
729
730
731
732
733
	s.loadedMu.Lock()
	runnerList := make([]*runnerRef, 0, len(s.loaded))
	for _, r := range s.loaded {
		runnerList = append(runnerList, r)
	}
	s.loadedMu.Unlock()
734
735
736
737
	if len(runnerList) == 0 {
		slog.Debug("no loaded runner to unload")
		return nil
	}
Daniel Hiltgen's avatar
Daniel Hiltgen committed
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767

	// In the future we can enhance the algorithm to be smarter about picking the optimal runner to unload
	// e.g., if we have multiple options, will one make room for the request?
	sort.Sort(ByDuration(runnerList))

	// First try to find a runner that's already idle
	for _, runner := range runnerList {
		runner.refMu.Lock()
		rc := runner.refCount
		runner.refMu.Unlock()
		if rc == 0 {
			slog.Debug("found an idle runner to unload")
			return runner
		}
	}
	// None appear idle, just wait for the one with the shortest duration
	slog.Debug("no idle runners, picking the shortest duration", "count", len(runnerList))
	return runnerList[0]
}

func (s *Scheduler) unloadAllRunners() {
	s.loadedMu.Lock()
	defer s.loadedMu.Unlock()
	for model, runner := range s.loaded {
		if runner.llama != nil {
			slog.Debug("shutting down runner", "model", model)
			runner.llama.Close()
		}
	}
}
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782

// If other runners are loaded, make sure the pending request will fit in system memory
// If not, pick a runner to unload, else return nil and the request can be loaded
func (s *Scheduler) maybeFindCPURunnerToUnload(req *LlmRequest, ggml *llm.GGML, gpus gpu.GpuInfoList) *runnerRef {
	slog.Debug("evaluating if CPU model load will fit in available system memory")
	estimate := llm.EstimateGPULayers(gpus, ggml, req.model.ProjectorPaths, req.opts)
	if estimate.TotalSize <= gpus[0].FreeMemory {
		slog.Debug("cpu inference mode, model fits in available system memory", "model", format.HumanBytes2(estimate.TotalSize), "available", format.HumanBytes2(gpus[0].FreeMemory))
		return nil
	}

	// TODO - optimization: try to find CPU only runners first, or partial offloads with enough in system memory to make room

	return s.findRunnerToUnload()
}