Linux perf rides the rocket

brendangregg.com

101 points·akerl_··7 comments

Relevant Ubuntu bug: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1317811

Relevant upstream discussion: http://www.spinics.net/lists/netdev/msg282340.html

"Rides the Rocket" is a reference to Quake. It's a pretty crude joke about getting shot by a rocket launcher in the classic Quake deathmatch. It's likely there because of the similar, "frags", which is what they called kills, gruesomely short for the same "fragmentation"

I see these most often on a EC2 PV instance's console when I'm watching it during instance termination. Apparently the (Ubuntu 14.04) kernel does something the xennet driver really doesn't like while shutting down.

is anyone aware of similar articles for any of the BSD flavors or other operating systems?

Brendan Gregg has written many articles and a few books about DTrace which is included in FreeBSD.

Depends how similar. This article was specifically about kernel line number and local variable tracing, which I've only seen Linux do.

If you mean general kernel debugging, then my book on DTrace covers multiple operating systems including FreeBSD, and has around a thousand pages of examples.

It would be nice if DTrace could add kernel line number and local variable tracing. Recently I've seen FreeBSD kernel builds where inlining has become more common than I've seen in the past, and missing kernel functions is becoming a bit of a nuisance. It's generally possible to work around it, but it would be nice to just trace lines and variables if needed.

> This is pretty amazing. perf shows line numbers of those that can be instrumented directly, and those that can't in blue.

That looks like it just came from debugging info. I.e. the numbered lines correspond to places where a debugger could put a breakpoint.

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