MAC OS 内核跟踪监视工具dtrace 使用示例说明
http://files.cnblogs.com/daizhj/DTrace.pdf//////////////////
syscall
dtrace -ln 'syscall::write*:' //显示可使用的probe
dtrace -ln 'syscall::*read*:entry' //显示可使用的probe
dtrace -n 'syscall::write:entry {@dist = quantize(arg0)}'//之后CTRL+C
dtrace -n 'syscall::socket:entry {@dist = quantize(arg0)}' //之后CTRL+C
dtrace -n 'syscall:::entry { @sc = count(); }'＃dtrace -n 'syscall:::entry'
dtrace -n 'syscall::open:entry { printf("%s %s", execname, copyinstr(arg0)); }'
dtrace -n 'syscall::fork*: { trace(pid); }'
dtrace -n 'syscall::exec*: { trace(execname); }'
Showing Read Byte Distributions by Process
dtrace -n 'syscall::read:return { @ = quantize(arg0); }'
一秒打印一次进程数
dtrace -n 'profile-997 { @ = count(); } tick-1s { printa(@); trunc(@); }'
Mostfunction calls will return from the same thread that they enter,6 so a thread- local variable can be used to associate these events. Here a time stamp is saved on the write(2) entry so that the time can be calculated on return:
dtrace -n 'syscall::write:entry { self->s = timestamp; } syscall::write:return /self->s/
syscall Provider
dtrace -n 'syscall:::entry { @ = count(); }'
Which processes are executing the most system calls?
dtrace -n 'syscall:::entry { @ = count(); }'
What system calls are a given process name executing (for example, firefox-bin)?
dtrace -n 'syscall:::entry /execname == "firefox"/ { @ = count(); }'
dtrace-qn 'syscall::read:entry,syscall::write:entry /fds.fi_fs == "sockfs"/ { @ = sum(arg2); } tick-1sec { printa(@); trunc(@);}'＃暂无打印
dtrace -n 'syscall::read:entry,syscall::write:entry /execname == "firefox" && fds.fi_fs == "sockfs"/ { @ = count(); }' ＃暂无打印
/////////////////////////
指定进程的MALLOC调用情况
dtrace -n 'pid$target::malloc:entry { @ = quantize(arg0); }' -p 513
//////////////////////
Disk I/O
dtrace -n 'io:::start { @ = count(); }'
bash-3.2# dtrace -qn 'syscall:::entry /execname == "firefox"/
{ @ = count(); } END { trunc(@, 10); printa(@); }'
dtrace -n 'syscall::pread*:entry,syscall::pwrite*:entry /execname == "java"/
{ @.fi_fs] = count(); }'
dtrace -n 'syscall::pread*:entry,syscall::pwrite*:entry /execname == "java"/
{ @.fi_pathname] = count(); }'
/////////////////////////
Memory
Tracking process user stack sizes:
Tracking which processes are growing their address space heap segment:
Tracking memory page faults by process name:
dtrace -n 'vminfo:::as_fault { @mem = sum(arg0); }'
Tracking pages paged in by process name:
dtrace -n 'vminfo:::pgpgin { @pg = sum(arg0); }'
Tracking pages paged out by process name:
dtrace -n 'vminfo:::pgpgout { @pg = sum(arg0); }'
sched Provider
dtrace -n 'sched:::on-cpu { @ = count(); }'
Tracking process user stack sizes:
dtrace -n 'sched:::on-cpu { @ = max(curthread->t_procp->p_stksize);}'
Tracking which processes are growing their address space heap segment:
dtrace -n 'fbt::brk:entry { @mem = count(); }'
fbt Provider
Tracking which processes are growing their address space stack segment:
dtrace -n 'fbt::grow:entry { @mem = count(); }'
///////////////////////////////////////////////////////
I/O
Which processes are executing common I/O system calls?
dtrace -n 'syscall::*read:entry,syscall::*write:entry { @rw =
count(); }'
Which file system types are targeted for reads and writes?
dtrace -n 'syscall::*read:entry,syscall::*write:entry { @fs.fi_fs] = count(); }'
Which files are being read, and by which processes?
dtrace -n 'syscall::*read:entry { @f.fi_pathname] = count(); }'
Which files are being written, and by which processes?
dtrace -n 'syscall::*write:entry { @f.fi_pathname] = count(); }'
Which processes are generating network I/O (Solaris)?
dtrace -n 'fbt:sockfs::entry { @ = count(); }'#暂时无法使用
What is the rate of disk I/O being issued?
dtrace -n 'io:::start { @io = count(); } tick-1sec { printa("Disk I/Os per second: %@d \n", @io); trunc(@io); }'
检查socket 调用情况
dtrace -n 'syscall::socket:entry{ @ = quantize(arg0); }'
dtrace -n 'syscall::write:entry /execname=="VineSample"/ { @ = quantize(arg0); }'
//////////////////////////////////////////////////////
lquantize解释：https://blogs.oracle.com/swan/entry/dtrace%E7%AE%80%E4%BB%8B_3
使用lquantize（所指定表达式的值的线性频率分布），我们了解需要调查的表达式的分布情况。比如，我们想知道系统调用write打开的文件描述符(file descriptor)的线性分布情况。
'syscall::write:entry{@fds=lquantize(arg0,0,100,1)}'#参数说明：标量表达式，下限，上限，步长值
dtrace: description 'syscall::write:entry' matched 1 probe
\^C
dtrace
value------------- Distribution ------------- count
0 | 0
1 |@@@@@@@@@@@@@@@@@@@@ 1
2 | 0
sshd
value------------- Distribution ------------- count
3 | 0
4 |@@@@@@@@@@@@@@@@@@@@ 1
5 | 0
6 | 0
7 | 0
8 |@@@@@@@@@@@@@@@@@@@@ 1
9 | 0
在上例中，我们可以看到，在该时间内，sshd进程对文件描述符4操作了1次，对文件描述符8操作了1次。虽然不具有实际意义，但可以帮助我们理解lquantize的作用。
如果要聚合的表达式的值非常大，使用lquantize可能会输出太多信息，这种情况下可以使用quantize（所指定表达式的值的二次方幂频率分布）来聚合。
下面是一个统计执行程序系统调用的时间分布的D脚本： time.d
#!/usr/sbin/dtrace -s
syscall:::entry
{
self->ts=timestamp;
}
syscall:::return
/self->ts/
{
@time=quantize(timestamp-self->ts);
}
执行一段时间，按Ctrl+C中断。限于篇幅，下面只列出部分信息。
# ./time.d
dtrace: script './time.d' matched 462 probes
\^C
sendmail
value------------- Distribution ------------- count
1024 | 0
2048 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 7
4096 |@@@@ 1
8192 |@@@@ 1
16384 | 0
sshd
value------------- Distribution ------------- count
1024 | 0
2048 |@@@@@@@@@@@@@@@@@@@ 7
4096 |@@@@@ 2
8192 |@@@@@ 2
16384 |@@@@@ 2
32768 | 0
65536 |@@@@@ 2
131072 | 0
以sendmail程序为例：
系统调用执行时间（从entry到return）在大于等于2048纳秒并小于4096纳秒区间共有7次，在大于等于4096纳秒小于8192纳秒区间共有1次，在大于等于8192纳秒小于16384纳秒区间共有1次。
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