DTrace

[mcheung63]

Hi all
I am not familar with DTrace. So I guess
1) solaris is using a fixed memory area or fixed file system location to store the informations that DTrace need. such as high-level process information, user activities, etc...
2) DTrace can dump a back-trace-function-call-graph. I guess solaris will record informations on every call-instruction.
3) Solaris will not decrease in performance when point-2 is implemented. I guess all the kernel modules have two version : dtrace-enable-version and non-enable-version. When the dtrace feature is on, the solaris dynamically switch all modules to the dtrace-enable one.

correct me please.
thanks
from Peter ([email protected])

[JamesM]

As was aptly mentioned by an anonymous user in their post report:

"Should be in general ramblings, or nowhere in fact, given the first three hits on google..."

QFT.

[pcmattman]

According to Wikipedia the code is available under the CDDL.

I'd say your best bet is to read the code or ask on a Solaris-themed forum.

[Dario]

Linux provides Dtrace alternative called SystemTap which, of course, is under GPL.
Still haven't tried it yet...

[fronty]

Linux provides Dtrace alternative called SystemTap which, of course, is under GPL.
Still haven't tried it yet...

It tries to be alternative, but it really isn't. I remember I've read some article/blog post by some of the DTrace team (Cantrill or Leventhal IIRC) about this. I'll try to find it. EDIT: Found it. http://blogs.sun.com/ahl/entry/dtrace_knockoffs

I haven't read DTrace source and haven't used it very much though I use Solaris and FreeBSD. I won't even guess what kind of (high) wizardry is involved in it, so it can be used without performance penalty on production server.

[Dario]

Linux's development process is relatively slow, but it's happening on many fronts at the same time. That's why BTRFS and SystemTap will take a while to become production ready. Also, Sun's engineers, especially Bryan, have tendency to over exaggerate Linux's issues, probably because Linux has affected Unix market so much, a field where Sun used to rule.
Also, I don't think that these two project really care about Dtrace or ZFS as much as Bryan says. Linux is known for not planing it's distance future, but rather dealing with current technical issues.
Personally, I would love to see Dtrace and ZFS fall under GPL and that might happen since Sun is owned by Oracle which heavily relies on Linux and invests a lot of code in to it. In fact Btrfs was started by Oracle's engineer. So they might conclude that it's more cheaper and profitable for them to provide production ready FS.

[Owen]

Linux's development process is relatively slow, but it's happening on many fronts at the same time. That's why BTRFS and SystemTap will take a while to become production ready. Also, Sun's engineers, especially Bryan, have tendency to over exaggerate Linux's issues, probably because Linux has affected Unix market so much, a field where Sun used to rule.
Also, I don't think that these two project really care about Dtrace or ZFS as much as Bryan says. Linux is known for not planing it's distance future, but rather dealing with current technical issues.
Personally, I would love to see Dtrace and ZFS fall under GPL and that might happen since Sun is owned by Oracle which heavily relies on Linux and invests a lot of code in to it. In fact Btrfs was started by Oracle's engineer. So they might conclude that it's more cheaper and profitable for them to provide production ready FS.

Relicensing ZFS or DTrace would heavily upset the OpenSolaris community, which wouldn't be the best of results (You wouldn't believe how many Oracle installs are on Solaris.)

The big problem with putting either under the GPL is that inevitably someone would fork them under it - and then (Open)Solaris couldn't take the improvements back.

[Dtrace]

http://crtags.blogspot.com
http://www.crisp.demon.co.uk/blog
source code: ftp://crisp.dynalias.com/pub/release/website/dtrace/

I've been working on it for a couple of years. Read the blog for tit bits on where the problems lay. This is a source only loadable dtrace driver, which patches the kernel, based on Sun's original source. Apart from static (SDT) probes (which i am working on), it works. You can probe any function or syscall in the kernel.

My current testbed is ubuntu 10.04 (64-bit) but it should work on much older kernels (tested back to 2.6.9) - it auto detects the kernels etc.

Give it a try and feedback. Its CDDL licensed, because it has to be; I would rather GPL it - but I dont really care for license politics.