SystemTap

安装
sudo apt-get install build-essential
sudo apt-get install elfutils
sudo apt-get install libdw-dev
wget wget https://sourceware.org/systemtap/ftp/releases/systemtap-2.4.tar.gz
tar -xzvf systemtap-2.4.tar.gz
cd systemtap-2.4
./configure
sudo make
sudo make install

測试语句
sudo stap --all-modules -ve 'probe begin { log("hello world") exit () }'
sudo stap -ve 'probe begin { log("hello world") exit () }'
sudo stap -ve 'probe kernel.function("sys_open") {log("hello world") exit()}'
sudo stap -ve 'probe module("libiscsi").function("iscsi_queuecommand") {log("hello world") exit()}'
打印堆栈
print_backtrace

--all-modules载入全部模块，显示堆栈信息

在Ubuntu上使用SystemTap
http://www.ningoo.net/html/2010/use_systemtap_on_ubuntu.html

ubuntu+systemtap进行Linux内核和用户空间开发測试
http://blog.csdn.net/sailor_8318/article/details/25076745

SystemTap在Ubuntu 12.04上的安装 Build-id mismatch
http://www.it165.net/os/html/201310/6486.html

使用systemtap调试linux内核
http://blog.csdn.net/heli007/article/details/7187748

利用systemtap定位ifconfig dropped数据包的原因
http://www.it165.net/os/html/201308/5944.html

范例
https://sourceware.org/systemtap/wiki

System语言具体解释
http://blog.csdn.net/linyt/article/details/5204841

#! /usr/bin/env stap 

global host_no = 17
global channel = 0
global targetid = 0
global lunid = 15

# 推断io是否下发到iscsi
probe module("libiscsi").function("iscsi_queuecommand")
{
    if ( $host!=0 && $sc!=0 )
    {
        if ( $host->host_no==host_no && $sc->device->channel==channel && $sc->device->id==targetid && $sc->device->lun==lunid )
        {
            printf("====================send scsi=======================
")
            printf("tag = %d
", $sc->tag)
            printf("serial_number = %lu
", $sc->serial_number)
            printf("jiffies_at_alloc = %lu
", $sc->jiffies_at_alloc)
            print_backtrace()        
            printf("
")
        }
    }
}


probe kernel.function("do_sync_read")
{
    if ($filp!=0)
    {
        if ($filp->f_inode!=0)
        {
            if ($filp->f_inode->i_ino == 3978543828)
            {
                printf("===========================================do_sync_read

")
            }
        }
    }
}

# 推断IO在iscsi被正确下发
probe module("libiscsi").statement("iscsi_queuecommand@libiscsi.c:1690")
{
    if ( $host!=0 && $sc!=0 )
    {
        if ( $host->host_no==host_no && $sc->device->channel==channel && $sc->device->id==targetid && $sc->device->lun==lunid )
        {
            printf("====================cmd sended=======================
")
            printf("reason=%d
", $reason)
            printf("
")
        }
    }
}

# 推断IO是否返回
probe module("libiscsi").function("__iscsi_put_task")
{
    if ($task != 0)
    {

        if ($task->sc != 0)
        {
            if ( $task->sc->device->host->host_no==host_no && $task->sc->device->channel==channel && $task->sc->device->id==targetid && $task->sc->device->lun==lunid )
            {
                printf("*************************recv scsi********************
")
                printf("tag = %d
", $task->sc->tag)
                printf("serial_number = %lu
", $task->sc->serial_number)
                printf("jiffies_at_alloc = %lu
", $task->sc->jiffies_at_alloc)
                print_backtrace()
                printf("
")
           }
        }
    }
}