Re: [RFC 1/2] kernel patch for dump user space stack tool

From: Peter Zijlstra
Date: Fri Apr 20 2012 - 05:38:45 EST

On Thu, 2012-04-19 at 13:17 +0800, Yanmin Zhang wrote:
> Although not checking the source codes of pstack (sorry, I'm busy in debugging
> many critical issues), I think pstack is based on ptrace interface, which means:
> 1) It need traps into system for many times to collect call frames of one
> task.
> 2) It need send signal to the ptraced process to stop it. Such behavior
> might have some impact if the ptraced process also processes many signals.

Yeah, but who cares.. its debugging stuff..

> 3) The data parsing to get symbols might not be split from data collection.
> I mean, it collects call frames of one process, then parses it; then collects the 2nd
> task's. If there are many processes, it couldn't collect the data just at the monitor
> time point.

This is equally true for your silly patch.

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