vfssize.bt

#!/usr/local/bin/bpftrace
/*
 * vfssize - Show VFS read/write sizes.
 *
 * See BPF Performance Tools, Chapter 8, for an explanation of this tool.
 *
 * Copyright (c) 2019 Brendan Gregg.
 * Licensed under the Apache License, Version 2.0 (the "License").
 * This was originally created for the BPF Performance Tools book
 * published by Addison Wesley. ISBN-13: 9780136554820
 * When copying or porting, include this comment.
 *
 * 17-Apr-2019  Brendan Gregg   Created this.
 */

#include <linux/fs.h>

kprobe:vfs_read,
kprobe:vfs_readv,
kprobe:vfs_write,
kprobe:vfs_writev
{
	@file[tid] = arg0;
}

kretprobe:vfs_read,
kretprobe:vfs_readv,
kretprobe:vfs_write,
kretprobe:vfs_writev
/@file[tid]/
{
	if (retval >= 0) {
		$file = (struct file *)@file[tid];
		$name = $file->f_path.dentry->d_name.name;
		if ((($file->f_inode->i_mode >> 12) & 15) == DT_FIFO) {
			@[comm, "FIFO"] = hist(retval);
		} else {
			@[comm, str($name)] = hist(retval);
		}
	}
	delete(@file[tid]);
}

END
{
	clear(@file);
}