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SystemTap enables the same kind of analysis for a few years already. And it works well with older kernels (starting from 3.2, but really from 3.13). Of course,
by vbernat 10y ago
SystemTap enables the same kind of analysis for a few years already. And it works well with older kernels (starting from 3.2, but really from 3.13). Of course, an in-kernel solution is better (and I believe that SystemTap will soon use it).
It's unfortunate that SystemTap never had much visbility. It also comes with a huge libraries of tapsets.
- dozzie 10y agoIs SystemTap stable already? As far as I remember from few years ago, it could easily crash your kernel with a valid program that didn't abuse anything, what disqualified it from use in production.
- josefbacik 10y agoSystemtap was fantastic, but super finnicky. You had to have debuginfo for the kernel installed plus the source. This was fine for RHEL but kind of a pain elsewhere. Then you run into other problems like sometimes the distro compiler wasn't used to build the kernel you are running and suddenly you couldn't load any stap script. Also the only way to get output was through stdout, there was no easy way to programmatically pull results from an stap script. BPF/BCC solves most of this. You still have to have the sources so you can get the right targets for kprobes, but you don't have the compiler mismatch problem. You can now access the hash maps directly from user space so you can do things like build system monitoring tools that run in production and record really specific information easily. I used systemtap for years, but bcc/bpf is a whole new world.
- paxcoder 10y agoYou used past tense in talking about a project last committed to less than 3 days ago. I have no horse in this race but it seems to me like you might.
- josefbacik 10y agoOr I just mistyped and you are reading in too much to it?
- ignoramous 10y agoIf you mistyped it, pls correct it.
- okket 10y agoYou can only edit a post for ~1 hour, his is 3 hours old...
- paxcoder 10y agoIt's not a typo, it's a theme driven home by your last sentence.
- kbenson 10y agoAnd that last sentence makes it obvious why he's using the past tense. Systemtap is in his past. When it was last committed to is irrelevant. If I was feeling less gracious, I might call into question whether you actually have no horse in this race, as apparently calling other people's motives and statements into question is apparently fair game for this thread.
- paxcoder 10y agoIt might have been clear had it been used to set the tone. But used like this I think it deserves criticism whether intentional or not. While I certainly can be be wrong, I also wasn't assured it wasn't intentional by the way it was explained. I suggest we all mind phrasing and get along this way. P.S. I don't find it gracious of you to imply that I might be a lying cheat.
- brendangregg 10y agoYes, and I've given SystemTap plenty of chances and hours of my time. But right now let's give BPF a chance -- it's more in-kernel in 2 years than SystemTap did in 10 years. > It's unfortunate that SystemTap never had much visbility. Right. DTrace was marketed. I don't think SystemTap was.