server/internal: copy bmizerany/ollama-go to internal package (#9294)

This commit copies (without history) the bmizerany/ollama-go repository
with the intention of integrating it into the ollama as a replacement
for the pushing, and pulling of models, and management of the cache they
are pushed and pulled from.

New homes for these packages will be determined as they are integrated
and we have a better understanding of proper package boundaries.

server/internal/cmd/oppbench/oppbench.go

@@ -0,0 +1,11 @@
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+func main() {
+	fmt.Println("Run as 'go test -bench=.' to run the benchmarks")
+	os.Exit(1)
+}

server/internal/cmd/oppbench/oppbench_test.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"runtime"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/ollama/ollama/server/internal/chunks"
+	"golang.org/x/sync/errgroup"
+)
+
+func BenchmarkDownload(b *testing.B) {
+	run := func(fileSize, chunkSize int64) {
+		name := fmt.Sprintf("size=%d/chunksize=%d", fileSize, chunkSize)
+		b.Run(name, func(b *testing.B) { benchmarkDownload(b, fileSize, chunkSize) })
+	}
+
+	run(100<<20, 8<<20)
+	run(100<<20, 16<<20)
+	run(100<<20, 32<<20)
+	run(100<<20, 64<<20)
+	run(100<<20, 128<<20) // 1 chunk
+}
+
+func run(ctx context.Context, c *http.Client, chunk chunks.Chunk) error {
+	const blobURL = "https://ollama.com/v2/x/x/blobs/sha256-4824460d29f2058aaf6e1118a63a7a197a09bed509f0e7d4e2efb1ee273b447d"
+	req, err := http.NewRequestWithContext(ctx, "GET", blobURL, nil)
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Range", fmt.Sprintf("bytes=%s", chunk))
+	res, err := c.Do(req)
+	if err != nil {
+		return err
+	}
+	defer res.Body.Close()
+
+	_, err = io.CopyN(io.Discard, res.Body, chunk.Size()) // will io.EOF on short read
+	return err
+}
+
+var sleepTime atomic.Int64
+
+func benchmarkDownload(b *testing.B, fileSize, chunkSize int64) {
+	client := &http.Client{
+		Transport: func() http.RoundTripper {
+			tr := http.DefaultTransport.(*http.Transport).Clone()
+			tr.DisableKeepAlives = true
+			return tr
+		}(),
+	}
+	defer client.CloseIdleConnections()
+
+	// warm up the client
+	run(context.Background(), client, chunks.New(0, 1<<20))
+
+	b.SetBytes(fileSize)
+	b.ReportAllocs()
+
+	// Give our CDN a min to breathe between benchmarks.
+	time.Sleep(time.Duration(sleepTime.Swap(3)))
+
+	for b.Loop() {
+		g, ctx := errgroup.WithContext(b.Context())
+		g.SetLimit(runtime.GOMAXPROCS(0))
+		for chunk := range chunks.Of(fileSize, chunkSize) {
+			g.Go(func() error { return run(ctx, client, chunk) })
+		}
+		if err := g.Wait(); err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func BenchmarkWrite(b *testing.B) {
+	b.Run("chunksize=1MiB", func(b *testing.B) { benchmarkWrite(b, 1<<20) })
+}
+
+func benchmarkWrite(b *testing.B, chunkSize int) {
+	b.ReportAllocs()
+
+	dir := b.TempDir()
+	f, err := os.Create(filepath.Join(dir, "write-single"))
+	if err != nil {
+		b.Fatal(err)
+	}
+	defer f.Close()
+
+	data := make([]byte, chunkSize)
+	b.SetBytes(int64(chunkSize))
+	r := bytes.NewReader(data)
+	for b.Loop() {
+		r.Reset(data)
+		_, err := io.Copy(f, r)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}