Re: [PATCH] x86_64: fix delayed signals

From: Linus Torvalds
Date: Fri Jul 11 2008 - 19:24:21 EST




On Fri, 11 Jul 2008, Linus Torvalds wrote:
>
> No, after testing more, I think Edwin is right.

Naah. It is true that there is a huge delay in doing

ls -l /usr/bin

and then pressing ^C, but after having hit my head against this for a
while, I realized that it has nothing to do with the kernel.

Doing an "strace ls" showed that ls doesn't play any games with signals
etc, which fooled me into looking for a kernel reason.

HOWEVER, it looks like at least fedora does a

alias ls='ls --color=auto'

and it turns out that if you do that --color=auto, then ls will indeed
catch all normal signals and set a "please stop now" flag, instead of
dying immediately. The reason is probably to avoiding leaving the terminal
with some odd color if interrupted in an inconvenient place.

So I was chasing this latency thing totally unnecessarily. It's in user
space (or at least _my_ particular issue was).

Other user cases may obviously be elsewhere.

Linus
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