Set default buffer pages appropriate for page size

The 1024 default for `--perf-buffer-size` and `--blob-perf-buffer-size`
assumes a 4KB page size to give 4MB of contiguous memory per perfbuffer.
But Arm and Powerpc architectures can have page sizes of 64KB and that
could require a lot of memory on servers with many cores as perfbuffers
are per cpu. Fix by calculating the defaults to give 4MB per perfbuffer.

Author: djoreilly

cmd/tracee/cmd/root.go

@@ -172,10 +172,11 @@ func initCmd() error {
 
 	// Buffer/Cache flags
 
+	defaultBufferPages := (4096 * 1024) / os.Getpagesize() // 4 MB of contiguous pages
 	rootCmd.Flags().IntP(
 		"perf-buffer-size",
 		"b",
-		1024, // 4 MB of contiguous pages
+		defaultBufferPages,
 		"<size>\t\t\t\tSize, in pages, of the internal perf ring buffer used to submit events from the kernel",
 	)
 	err = viper.BindPFlag("perf-buffer-size", rootCmd.Flags().Lookup("perf-buffer-size"))
@@ -185,7 +186,7 @@ func initCmd() error {
 
 	rootCmd.Flags().Int(
 		"blob-perf-buffer-size",
-		1024, // 4 MB of contiguous pages
+		defaultBufferPages,
 		"<size>\t\t\t\tSize, in pages, of the internal perf ring buffer used to send blobs from the kernel",
 	)
 	err = viper.BindPFlag("blob-perf-buffer-size", rootCmd.Flags().Lookup("blob-perf-buffer-size"))

tests/integration/tracee.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"os"
 	"path/filepath"
 	"strconv"
 	"sync"
@@ -94,8 +95,9 @@ func startTracee(ctx context.Context, t *testing.T, cfg config.Config, output *c
 
 	cfg.Capture = capture
 
-	cfg.PerfBufferSize = 1024
-	cfg.BlobPerfBufferSize = 1024
+	defaultBufferPages := (4096 * 1024) / os.Getpagesize() // 4 MB of contiguous pages
+	cfg.PerfBufferSize = defaultBufferPages
+	cfg.BlobPerfBufferSize = defaultBufferPages
 	cfg.PipelineChannelSize = 10000
 
 	// No process tree in the integration tests