Strace - The Sysadmin's Microscope
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Strace - The Sysadmin's Microscope
1–10 of 25 posts
Re: Strace - The Sysadmin's Microscope
#2I use strace all the time (and ltrace too)... I honestly don't know how people get by without it...
BTW, the Windows equivalent is called "Process Monitor" from the SysInternals guy...
Re: Strace - The Sysadmin's Microscope
#3strace tip #31415927: If your program is I/O bound, sometimes you can improve performance by increasing the size of the read buffer. A bigger buffer means fewer system calls and potentially increased performance. How do you know how big the read buffer is? Sometimes it's hard to tell even if you have the source (i.e. you're using stdio). With strace you can see the number of bytes you're trying to slurp in with each read system call. If it looks like a small number, you can then go figure out how to make it a bigger number, perhaps using setvbuf or rolling your own buffered I/O.
Re: Strace - The Sysadmin's Microscope
#4Does anyone know of a usable (no sudo needed) strace for Darwin / OS X?
Re: Strace - The Sysadmin's Microscope
#5What are the args to make Mac OS's "dtrace" behave like "strace" does when given no options?
Re: Strace - The Sysadmin's Microscope
#6Also very useful: ltrace.
ltrace is like strace, but does library calls instead of system calls.
Re: Strace - The Sysadmin's Microscope
#7OS X has a fancy GUI for this called Instruments.
(Obviously the cmdline tools are there as well.)
Re: Strace - The Sysadmin's Microscope
#8What are the args to make Mac OS's "dtrace" behave like "strace" does when given no options?
Look at dtruss.
Unfortunately you need to "sudo" to use it, since dtrace needs root permsisions.
Re: Strace - The Sysadmin's Microscope
#9Does anyone know of a usable (no sudo needed) strace for Darwin / OS X?
This is a tangent but why is sudo needed != usable?
Re: Strace - The Sysadmin's Microscope
#10It's also worth looking at SystemTap or DTrace, depending on what OS you're running. While strace will allow you to look at an individual process and its children, SystemTap/DTrace will allow you to gather data on system call (and then some) usage system wide. Some examples:
- monitor execve() calls system-wide
- monitor I/O to a specific file, from any process
- measure per-process network usage
(note that newer Linux kernels may have other ways of accomplishing some of these tasks that I'm not aware of).
I've had a lot of success using SystemTap to look at low-level filesystem performance issues in the kernel. We've run SystemTap scripts on our production filesystem servers for over a year with no problems whatsoever.
Edit: formatting