similar to: [LLVMdev] Lazy JIT thread safety

On Wed, Oct 28, 2009 at 9:57 AM, Jeffrey Yasskin <jyasskin at google.com> wrote: > On Wed, Oct 28, 2009 at 9:50 AM, Chris Lattner <clattner at apple.com> wrote: >> >> On Oct 28, 2009, at 9:41 AM, Jeffrey Yasskin wrote: >> >>> In r85295, in response to the discussion at http://llvm.org/PR5184 >>> (Lazy JIT ain't thread-safe), I changed the

On Wed, Oct 28, 2009 at 9:50 AM, Chris Lattner <clattner at apple.com> wrote: > > On Oct 28, 2009, at 9:41 AM, Jeffrey Yasskin wrote: > >> In r85295, in response to the discussion at http://llvm.org/PR5184 >> (Lazy JIT ain't thread-safe), I changed the default JIT from lazy to >> non-lazy. It has since come to my attention that this may have been >> the

>From where I sit, this boils down to a very simple question (modulo Chris's point): Either choice will surprise some users. Which surprise is worse? Personally, I'd always prefer correct but slow behavior by default, and explicitly enabling dangerous (but in some cases fast) behavior. I would also point out that it seems that most of the people new to the JIT are surprised by the

A possible patch implementing this is at http://codereview.appspot.com/144074 (http://codereview.appspot.com/download/issue144074_1.diff). I do NOT think we should accept this patch: It changes a lot of APIs and makes users specify the choice in many places, while I think most users really just want one choice for their whole app. There's a good argument to be made that users may want to

In r85295, in response to the discussion at http://llvm.org/PR5184 (Lazy JIT ain't thread-safe), I changed the default JIT from lazy to non-lazy. It has since come to my attention that this may have been the wrong change, so I wanted to ask you guys. A couple reasons to make the default non-lazy compilation: * The lack of thread-safety surprises new users * Crashes due to this will be rare

Are you objecting to Chris's proposal? I was waiting to implement it until you replied so I wouldn't have to implement two things. I disagree with a lot of what you wrote below, but it's not worth arguing about if there's a compromise we can both live with. On Thu, Oct 29, 2009 at 12:36 AM, Evan Cheng <evan.cheng at apple.com> wrote: > There is nothing here that prevents

On Oct 28, 2009, at 9:41 AM, Jeffrey Yasskin wrote: > In r85295, in response to the discussion at http://llvm.org/PR5184 > (Lazy JIT ain't thread-safe), I changed the default JIT from lazy to > non-lazy. It has since come to my attention that this may have been > the wrong change, so I wanted to ask you guys. > > A couple reasons to make the default non-lazy compilation:

On Thu, Oct 29, 2009 at 2:30 PM, Nicolas Geoffray <nicolas.geoffray at lip6.fr> wrote: > Hi Jeffrey, > > Jeffrey Yasskin wrote: >> >> Cool, I'll start implementing it. >> > > Great! Thanks. > > Just to clarify things: on my end, it doesn't really matter what is the > default behavior, as long as vmkit can continue to have the existing >

Cool, I'll start implementing it. Thanks all for the decision! On Thu, Oct 29, 2009 at 11:03 AM, Evan Cheng <evan.cheng at apple.com> wrote: > I have no objection to Chris' proposal. > > Evan > > On Oct 29, 2009, at 9:45 AM, Jeffrey Yasskin wrote: > >> Are you objecting to Chris's proposal? I was waiting to implement it >> until you replied so I

There is nothing here that prevents users from enabling or disabling lazy JIT. We're talk about flipping the default behavior. That does not make the API any better or worse. Nor does it fix the inherent thread safety issue. I can tell you there are no Apple clients that depend on the lazy JIT. Please do not imply I am being secretive. I am simply busy. My objection is simple.

On Wed, Oct 28, 2009 at 12:21 PM, Evan Cheng <evan.cheng at apple.com> wrote: > > On Oct 28, 2009, at 10:07 AM, Chandler Carruth wrote: > >> From where I sit, this boils down to a very simple question (modulo >> Chris's point): Either choice will surprise some users. Which surprise >> is worse? Personally, I'd always prefer correct but slow behavior by

Hi Jeffrey, Jeffrey Yasskin wrote: > Cool, I'll start implementing it. > Great! Thanks. Just to clarify things: on my end, it doesn't really matter what is the default behavior, as long as vmkit can continue to have the existing behavior of lazy compilation. With Chris' solution, I was wondering how you would implement the getPointerToFunction{Eager, Lazy} functions when

I have no objection to Chris' proposal. Evan On Oct 29, 2009, at 9:45 AM, Jeffrey Yasskin wrote: > Are you objecting to Chris's proposal? I was waiting to implement it > until you replied so I wouldn't have to implement two things. I > disagree with a lot of what you wrote below, but it's not worth > arguing about if there's a compromise we can both live with.

On Oct 28, 2009, at 10:07 AM, Chandler Carruth wrote: > From where I sit, this boils down to a very simple question (modulo > Chris's point): Either choice will surprise some users. Which surprise > is worse? Personally, I'd always prefer correct but slow behavior by > default, and explicitly enabling dangerous (but in some cases fast) > behavior. The behavior is only

On 2009-11-01 08:40, Jeffrey Yasskin wrote: > 2009/10/30 Török Edwin <edwintorok at gmail.com>: > >> On 2009-10-29 23:55, Jeffrey Yasskin wrote: >> >>> On Thu, Oct 29, 2009 at 2:30 PM, Nicolas Geoffray >>> <nicolas.geoffray at lip6.fr> wrote: >>> >>> >>>> Hi Jeffrey, >>>> >>>>

On Wed, Oct 28, 2009 at 11:41 AM, Jeffrey Yasskin <jyasskin at google.com> wrote: > And a couple to default to lazy compilation: > * It's safe for single-threaded code. > * There are existing users who have assumed this default. And what might break if this assumption doesn't hold?

2009/10/30 Török Edwin <edwintorok at gmail.com>: > On 2009-10-29 23:55, Jeffrey Yasskin wrote: >> On Thu, Oct 29, 2009 at 2:30 PM, Nicolas Geoffray >> <nicolas.geoffray at lip6.fr> wrote: >> >>> Hi Jeffrey, >>> >>> Jeffrey Yasskin wrote: >>> >>>> Cool, I'll start implementing it. >>>> >>>>

On 2009-10-29 23:55, Jeffrey Yasskin wrote: > On Thu, Oct 29, 2009 at 2:30 PM, Nicolas Geoffray > <nicolas.geoffray at lip6.fr> wrote: > >> Hi Jeffrey, >> >> Jeffrey Yasskin wrote: >> >>> Cool, I'll start implementing it. >>> >>> >> Great! Thanks. >> >> Just to clarify things: on my end, it

Thanks Jeffrey ! If possible, keep me inform (on revision number), I'm interested to see how you will do the unit test. (For my future patch... :) ). Thanks again. Olivier. On Wed, Feb 10, 2010 at 6:22 PM, Jeffrey Yasskin <jyasskin at google.com>wrote: > Thanks for the patch! I'll clean this up, convert your sample to a > unit test, and commit it for 2.7. > > On Sun,

On Fri, Mar 27, 2009 at 2:25 PM, Jeffrey Yasskin <jyasskin at google.com> wrote: > On Fri, Mar 27, 2009 at 3:48 PM, Evan Cheng <evan.cheng at apple.com> wrote: >> Run with -debug-only=jit. > > OT: I take it the recommended model for tools that embed LLVM is for > them to accept all of LLVM's command line arguments on their own > command lines? Well, sort of...