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Linux Performance Analysis and Tools

dtrace.org

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Re: Linux Performance Analysis and Tools

#11
post #6

I recently dove into this area in an attempt to find something like strace that didn't cost as much (as the slides mention, it's hundreds of times slower to run something under strace). It seems like dtrace can likely do what I want, but it doesn't sound reliable under linux yet. Does anyone know if the native linux profiling tools can be used to answer questions like "which files is my process accessing"? As far as…

Ktap was recently announced also https://github.com/ktap/ktap

Re: Linux Performance Analysis and Tools

#12
post #9
post #5

Earlier quoted context omitted.

I want to point out a comment [1] apparently by the former chief open source evangelist, Danese Cooper [2], on the "Fork Yeah!" video contradicting Bryan Cantrill on this point. Here it is reproduced: Lovely except it really was decided to explicitly make OpenSolaris incompatible with GPL. That was one of the design points of the CDDL. I was in that room, Bryan and you were not, but I know its fun to re-write history…

> Lovely except it really was decided to explicitly make OpenSolaris incompatible with GPL. In fairness to both sides, pretty much everything that isn't GPL can be said to be incompatible with GPL, and almost anyone who decides to use something different than the GPL can be said to be deliberately incompatible with the GPL. That's just the nature of the GPL.

Permissive open-source licenses (MIT, BSD, etc.) are GPL-compatible. But I think the question here is more one of motivation: was a decision made for reason X which had the side-effect of making DTrace's license incompatible with Linux, or was the choice of license made specifically to cause that effect? There appear to be conflicting accounts from people who were at Sun at the time.

Re: Linux Performance Analysis and Tools

#13
post #5

Earlier quoted context omitted.

DTrace was deliberately licensed in a way to be incompatible with the Linux kernel. This was commented on directly by Bryan Cantrill on HN [1]. You should also watch his "Fork Yeah!" [2] and "Corporate Open Source Anti-Patterns" [3] talks for full context. [1]: https://news.ycombinator.com/item?id=4357507 [2]: http://www.youtube.com/watch?v=-zRN7XLCRhc [3]: http://www.youtube.com/watch?v=NhgXQFk9noI

I want to point out a comment [1] apparently by the former chief open source evangelist, Danese Cooper [2], on the "Fork Yeah!" video contradicting Bryan Cantrill on this point. Here it is reproduced: Lovely except it really was decided to explicitly make OpenSolaris incompatible with GPL. That was one of the design points of the CDDL. I was in that room, Bryan and you were not, but I know its fun to re-write history…

Danese is wrong. Ask the other people involved; they don't agree with her.

Almost any copyleft license that Sun could have chosen at the time would have been incompatible with the GPL; and multi-licensing wasn't seen as a viable option.

It's all a moot point now anyway, but I wish some individuals would stop acting like Danese is the sole truthful source on this just because it fits their armchair conspiracy theories.

Re: Linux Performance Analysis and Tools

#14
post #9

Earlier quoted context omitted.

> Lovely except it really was decided to explicitly make OpenSolaris incompatible with GPL. In fairness to both sides, pretty much everything that isn't GPL can be said to be incompatible with GPL, and almost anyone who decides to use something different than the GPL can be said to be deliberately incompatible with the GPL. That's just the nature of the GPL.

Permissive open-source licenses (MIT, BSD, etc.) are GPL-compatible. But I think the question here is more one of motivation: was a decision made for reason X which had the side-effect of making DTrace's license incompatible with Linux, or was the choice of license made specifically to cause that effect? There appear to be conflicting accounts from people who were at Sun at the time.

> Permissive open-source licenses (MIT, BSD, etc.) are GPL-compatible.

I guess I have a problem characterizing them that way since the traffic is going to be purely one-way. The GPL code can't be used by the projects with more permissive licenses without some kind of dual licensing, can it?

Re: Linux Performance Analysis and Tools

#15

Earlier quoted context omitted.

Permissive open-source licenses (MIT, BSD, etc.) are GPL-compatible. But I think the question here is more one of motivation: was a decision made for reason X which had the side-effect of making DTrace's license incompatible with Linux, or was the choice of license made specifically to cause that effect? There appear to be conflicting accounts from people who were at Sun at the time.

> Permissive open-source licenses (MIT, BSD, etc.) are GPL-compatible. I guess I have a problem characterizing them that way since the traffic is going to be purely one-way. The GPL code can't be used by the projects with more permissive licenses without some kind of dual licensing, can it?

It depends on what level of compatibility we're looking at. It's true that MIT-licensed code can migrate to a GPL codebase but not vice-versa. But a different kind of compatibility (what I was thinking of) is whether you can maintain separate and separately-licensed codebases and legally distribute the combined binary. If DTrace were MIT and the Linux kernel were GPL, you could legally link them and distribute the result, so in that sense they'd be "compatible". Which isn't the case if you have a CDDL and a GPL codebase.

Re: Linux Performance Analysis and Tools

#16
post #5

Earlier quoted context omitted.

I want to point out a comment [1] apparently by the former chief open source evangelist, Danese Cooper [2], on the "Fork Yeah!" video contradicting Bryan Cantrill on this point. Here it is reproduced: Lovely except it really was decided to explicitly make OpenSolaris incompatible with GPL. That was one of the design points of the CDDL. I was in that room, Bryan and you were not, but I know its fun to re-write history…

Danese is wrong. Ask the other people involved; they don't agree with her. Almost any copyleft license that Sun could have chosen at the time would have been incompatible with the GPL; and multi-licensing wasn't seen as a viable option. It's all a moot point now anyway, but I wish some individuals would stop acting like Danese is the sole truthful source on this just because it fits their armchair conspiracy theories…

Danese actually _wrote the licence_ as per the requirements set to her by the Sun management. She is as such the foremost authority on this of those who has publically spoken on the subject.

Who are these 'other people involved'? Involved in what? Unless they were involved in the licence creation what do they really know?

She (Danese) is not 'wrong', she is either outright lying (to what end?) or telling the truth. Again she, as the person who actually wrote the licence obviously knows the truth.

And how is it an 'armchair conspiracy theory' that the Sun management did not want to allow Linux (their main competitor who was also eating their lunch in the marketplace) to use the technology they (Sun) was open sourcing?

From a business standpoint it makes perfect sense, and thus is entirely plausible.

That doesn't mean that there weren't Sun developers who had no interest in denying Linux use of Solaris 'tech, but they were not calling the shots, Sun management was. And again from a management perspective it makes no sense to give away your advantages to your main competitor.

Re: Linux Performance Analysis and Tools

#17
post #6

I recently dove into this area in an attempt to find something like strace that didn't cost as much (as the slides mention, it's hundreds of times slower to run something under strace). It seems like dtrace can likely do what I want, but it doesn't sound reliable under linux yet. Does anyone know if the native linux profiling tools can be used to answer questions like "which files is my process accessing"? As far as…

You could link your library to a passthrough libc that logs calls, if it is dynamically linked. There are various library hijacking solutions to make it easier. ptrace, that strace uses is necessarily slow (ktrace in eg NetBSD is much faster, the kernel does the tracing not userspace).

Re: Linux Performance Analysis and Tools

#18
post #8
post #6

I recently dove into this area in an attempt to find something like strace that didn't cost as much (as the slides mention, it's hundreds of times slower to run something under strace). It seems like dtrace can likely do what I want, but it doesn't sound reliable under linux yet. Does anyone know if the native linux profiling tools can be used to answer questions like "which files is my process accessing"? As far as…

Try lsof for files accessed by process.

Correct me if I'm wrong here, but I believe lsof can only display files held open at a given point in time (when you run lsof), no? So if a process opens a file, does something with it, and then immediately closes it, you're unlikely to be able to catch that with lsof unless you happen to run it at exactly the right time.

Re: Linux Performance Analysis and Tools

#19

Earlier quoted context omitted.

Danese is wrong. Ask the other people involved; they don't agree with her. Almost any copyleft license that Sun could have chosen at the time would have been incompatible with the GPL; and multi-licensing wasn't seen as a viable option. It's all a moot point now anyway, but I wish some individuals would stop acting like Danese is the sole truthful source on this just because it fits their armchair conspiracy theories…

Danese actually _wrote the licence_ as per the requirements set to her by the Sun management. She is as such the foremost authority on this of those who has publically spoken on the subject. Who are these 'other people involved'? Involved in what? Unless they were involved in the licence creation what do they really know? She (Danese) is not 'wrong', she is either outright lying (to what end?) or telling the truth. A…

Danese is not actually the foremost authority on this, and she did not really "write the license". The license is based on the MPL (Mozilla Public License), and was written by Sun's legal staff in consultation with management and others inside of Sun at the time.

I know it would be wonderful to just wrap the licensing conspiracy theories up in a pretty bow because it fits your logical conclusions, but it isn't that simple.

I'm not saying that Danese is lying, just that she is wrong. There is a difference. Danese may have believed that it was done for the reasons she claims, but that doesn't make it so just because it's convenient to believe it.

There are far more people that have said that Danese is wrong that are qualified to do so; with that, I feel safe in saying she is wrong (nevermind my own involvement).

Re: Linux Performance Analysis and Tools

#20

Earlier quoted context omitted.

Danese actually _wrote the licence_ as per the requirements set to her by the Sun management. She is as such the foremost authority on this of those who has publically spoken on the subject. Who are these 'other people involved'? Involved in what? Unless they were involved in the licence creation what do they really know? She (Danese) is not 'wrong', she is either outright lying (to what end?) or telling the truth. A…

Danese is not actually the foremost authority on this, and she did not really "write the license". The license is based on the MPL (Mozilla Public License), and was written by Sun's legal staff in consultation with management and others inside of Sun at the time. I know it would be wonderful to just wrap the licensing conspiracy theories up in a pretty bow because it fits your logical conclusions, but it isn't that s…

>Danese is not actually the foremost authority on this

Who else would be? And yes, she did write the CDDL according to both herself and according to Simon Phipps, certainly it was scrutinised and possibly altered by Sun legal staff, but her writing it (as per the prerequisites made to her by Sun management) is undisputed. It doesn't matter if the licence was based upon MPL, the final licence is not MPL, it instead reflects the requests put upon Danese by that of Sun's management (and legal staff).

>but that doesn't make it so just because it's convenient to believe it.

You are the one denying the words of Danese while offering nothing whatsoever to support your claims.

All you are doing is to claim that trusting the words of the person who wrote the licence is akin to buying into 'conspiracy theories', nevermind that everything she said also makes perfect sense from a business standpoint.

If anything comes across as a 'fairy tale', it's the idea that Sun would allow Linux to incorporate Sun's technical advantages at a point where they were losing to Linux in the marketplace.

The person who wrote the licence claims she was told to prevent this, business logic strongly supports her claims, yet you pretend it's some 'conspiracy theory' while offering nothing to support your claims.

>I'm not saying that Danese is lying, just that she is wrong.

Come on, she is either lying or she is telling the truth, you keep trying to dance around this. She (Danese) wrote the licence (nothing has been put forth disputing this), she says that making it GPLv2 (Linux) incompatible was a prerequisite. She either lies or she is telling the truth.

I believe her because:

A) I can't think of any reason for her to lie B) it makes perfect sense from a business perspective

>There are far more people that have said that Danese is wrong that are qualified to do so

How are they qualified?

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