Switch back to subprocessing for llama.cpp

This should resolve a number of memory leak and stability defects by allowing
us to isolate llama.cpp in a separate process and shutdown when idle, and
gracefully restart if it has problems.  This also serves as a first step to be
able to run multiple copies to support multiple models concurrently.

llm/payload.go

@@ -0,0 +1,211 @@
+package llm
+
+import (
+	"compress/gzip"
+	"errors"
+	"fmt"
+	"io"
+	"io/fs"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"golang.org/x/exp/slices"
+	"golang.org/x/sync/errgroup"
+
+	"github.com/ollama/ollama/gpu"
+)
+
+var errPayloadMissing = fmt.Errorf("expected payloads not included in this build of ollama")
+
+func Init() error {
+	payloadsDir, err := gpu.PayloadsDir()
+	if err != nil {
+		return err
+	}
+
+	slog.Info("extracting embedded files", "dir", payloadsDir)
+	binGlob := "build/*/*/*/bin/*"
+
+	// extract server libraries
+	err = extractFiles(payloadsDir, binGlob)
+	if err != nil {
+		return fmt.Errorf("extract binaries: %v", err)
+	}
+
+	var variants []string
+	for v := range availableServers() {
+		variants = append(variants, v)
+	}
+	slog.Info(fmt.Sprintf("Dynamic LLM libraries %v", variants))
+	slog.Debug("Override detection logic by setting OLLAMA_LLM_LIBRARY")
+
+	return nil
+}
+
+// binary names may contain an optional variant separated by '_'
+// For example, "ollama_rocm_v6" and "ollama_rocm_v5" or "ollama_cpu" and "ollama_cpu_avx2"
+// Any library without a variant is the lowest common denominator
+func availableServers() map[string]string {
+	payloadsDir, err := gpu.PayloadsDir()
+	if err != nil {
+		slog.Error("payload lookup error", "error", err)
+		return nil
+	}
+
+	// glob payloadsDir for files that start with ollama_
+	pattern := filepath.Join(payloadsDir, "*")
+
+	files, err := filepath.Glob(pattern)
+	if err != nil {
+		slog.Debug("could not glob", "pattern", pattern, "error", err)
+		return nil
+	}
+
+	servers := make(map[string]string)
+	for _, file := range files {
+		slog.Debug("availableServers : found", "file", file)
+		servers[filepath.Base(file)] = file
+	}
+
+	return servers
+}
+
+// serversForGpu returns a list of compatible servers give the provided GPU
+// info, ordered by performance. assumes Init() has been called
+// TODO - switch to metadata based mapping
+func serversForGpu(info gpu.GpuInfo) []string {
+	// glob workDir for files that start with ollama_
+	availableServers := availableServers()
+	requested := info.Library
+	if info.Variant != "" {
+		requested += "_" + info.Variant
+	}
+
+	servers := []string{}
+
+	// exact match first
+	for a := range availableServers {
+		if a == requested {
+			servers = []string{a}
+
+			if a == "metal" {
+				return servers
+			}
+
+			break
+		}
+	}
+
+	alt := []string{}
+
+	// Then for GPUs load alternates and sort the list for consistent load ordering
+	if info.Library != "cpu" {
+		for a := range availableServers {
+			if info.Library == strings.Split(a, "_")[0] && a != requested {
+				alt = append(alt, a)
+			}
+		}
+
+		slices.Sort(alt)
+		servers = append(servers, alt...)
+	}
+
+	// Load up the best CPU variant if not primary requested
+	if info.Library != "cpu" {
+		variant := gpu.GetCPUVariant()
+		// If no variant, then we fall back to default
+		// If we have a variant, try that if we find an exact match
+		// Attempting to run the wrong CPU instructions will panic the
+		// process
+		if variant != "" {
+			for cmp := range availableServers {
+				if cmp == "cpu_"+variant {
+					servers = append(servers, cmp)
+					break
+				}
+			}
+		} else {
+			servers = append(servers, "cpu")
+		}
+	}
+
+	if len(servers) == 0 {
+		servers = []string{"cpu"}
+	}
+
+	return servers
+}
+
+// extract extracts the embedded files to the target directory
+func extractFiles(targetDir string, glob string) error {
+	files, err := fs.Glob(libEmbed, glob)
+	if err != nil || len(files) == 0 {
+		return errPayloadMissing
+	}
+
+	if err := os.MkdirAll(targetDir, 0o755); err != nil {
+		return fmt.Errorf("extractFiles could not mkdir %s: %v", targetDir, err)
+	}
+
+	g := new(errgroup.Group)
+
+	// build/$OS/$GOARCH/$VARIANT/{bin,lib}/$FILE
+	for _, file := range files {
+		filename := file
+
+		variant := filepath.Base(filepath.Dir(filepath.Dir(filename)))
+
+		slog.Debug("extracting", "variant", variant, "file", filename)
+
+		g.Go(func() error {
+			srcf, err := libEmbed.Open(filename)
+			if err != nil {
+				return err
+			}
+			defer srcf.Close()
+
+			src := io.Reader(srcf)
+			if strings.HasSuffix(filename, ".gz") {
+				src, err = gzip.NewReader(src)
+				if err != nil {
+					return fmt.Errorf("decompress payload %s: %v", filename, err)
+				}
+				filename = strings.TrimSuffix(filename, ".gz")
+			}
+
+			variantDir := filepath.Join(targetDir, variant)
+			if err := os.MkdirAll(variantDir, 0o755); err != nil {
+				return fmt.Errorf("extractFiles could not mkdir %s: %v", variantDir, err)
+			}
+
+			base := filepath.Base(filename)
+			destFilename := filepath.Join(variantDir, base)
+
+			_, err = os.Stat(destFilename)
+			switch {
+			case errors.Is(err, os.ErrNotExist):
+				destFile, err := os.OpenFile(destFilename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0o755)
+				if err != nil {
+					return fmt.Errorf("write payload %s: %v", filename, err)
+				}
+				defer destFile.Close()
+				if _, err := io.Copy(destFile, src); err != nil {
+					return fmt.Errorf("copy payload %s: %v", filename, err)
+				}
+			case err != nil:
+				return fmt.Errorf("stat payload %s: %v", filename, err)
+			}
+			return nil
+		})
+	}
+
+	err = g.Wait()
+	if err != nil {
+		// If we fail to extract, the payload dir is unusable, so cleanup whatever we extracted
+		gpu.Cleanup()
+		return err
+	}
+	return nil
+}