similar to: Effect of qemu-img convert -m and -W options

On Wed, Nov 15, 2017 at 11:52:46AM +0000, Richard W.M. Jones wrote: > [CC to qemu-devel since I'm obviously doing something wrong here, > I'm just not sure what.] > > I was getting ready to add multiple threads to ‘qemu-img convert’ (the > longest part of v2v conversions) when I noticed that it had them > already! (To be fair this was only added in February this year so

Am 16.11.2017 um 15:47 schrieb Stefan Hajnoczi: > On Wed, Nov 15, 2017 at 11:52:46AM +0000, Richard W.M. Jones wrote: >> [CC to qemu-devel since I'm obviously doing something wrong here, >> I'm just not sure what.] >> >> I was getting ready to add multiple threads to ‘qemu-img convert’ (the >> longest part of v2v conversions) when I noticed that it had them

On Thu, Nov 16, 2017 at 02:47:46PM +0000, Stefan Hajnoczi wrote: > The threads you observed are the thread pool that performs > preadv(2)/pwritev(2) syscalls. The Linux AIO API could be used instead > and does not use threads for read and write operations. I guess if I used AIO then I wouldn't get any parallelism at all since Linux doesn't block on local file access (at least,

On Thu, Nov 16, 2017 at 3:10 PM, Richard W.M. Jones <rjones@redhat.com> wrote: > On Thu, Nov 16, 2017 at 02:47:46PM +0000, Stefan Hajnoczi wrote: >> The threads you observed are the thread pool that performs >> preadv(2)/pwritev(2) syscalls. The Linux AIO API could be used instead >> and does not use threads for read and write operations. > > I guess if I used AIO

This is a quick hack to experiment with parallel threading model in the python plugin. Changes: - Use aligned buffers to make it possible to use O_DIRECT. Using parallel I/O does not buy us much when using buffered I/O. pwrite() copies data to the page cache, and pread() reads data from the page cache. - Disable extents in the file plugin. This way we can compare it with the python

Hi all: Below is a proposal to add experimental coroutine support to LLVM. Though this proposal is motivated primarily by the desire to support C++ Coroutines [1], the llvm representation is language neutral and can be used to support coroutines in other languages as well. Clang + llvm coroutines allows you to take this code: generator<int> range(int from, int to) { for(int i =

cc llvm-dev On Thu, Jul 21, 2016 at 9:57 AM, Vadim Chugunov <vadimcn at gmail.com> wrote: > Hi Gor, > Does you design support resumption with parameter(s)? (such as Python's > generator.send(x)). I suppose the "promise" could be used for passing data > both ways, but if that's the plan, please mention this explicitly in the > design doc. > Also, how is

Hello all, It's been a month since my previous email on the topic, and since then I've done some initial work on porting the coroutines passes to the new pass manager. In total there are 6 patches -- that's a lot to review, so allow me to introduce the changes being made in each of them. # What's finished In these first 6 patches, I focused on lowering coroutine intrinsics

Hi llvmdev! I've been working on adding coroutines to LLVM. Mentioned below is the implementation plan I'm following, for suggestions, flames and other input. Using segmented stacks is a prerequisite. The idea is to associate every coroutine with a coroutine descriptor. A coroutine descriptor consists of four words: w0, w1, w2 and w3. w0 always contains the _launcher_, and invoking a

Summary I would like to propose that we add the following function attribute to LLVM: synthetic(<string>) This attribute can only be applied to functions. It is not a semantic statement about the function it decorates. It is, instead, an explicit directive to LLVM to not attempt to propagate information about the function body outside of the function, including by changing the

On 07/28/2011 05:31 PM, Sanjoy Das wrote: > Hi llvmdev! > > I've been working on adding coroutines to LLVM. Mentioned below is the > implementation plan I'm following, for suggestions, flames and other > input. Using segmented stacks is a prerequisite. I think my only comment is that, while this would probably work, implementing it in C with a bit of assembly for

On Mon, Apr 12, 2010 at 6:15 AM, Kenneth Uildriks <kennethuil at gmail.com> wrote: > I created a wiki at http://code.google.com/p/llvm-stack-switch/ > > Right now I just copied and formatted the document as-is... I'll go > back over it with your comments in mind soon.  One more question, > which you can answer here or there: > >> Point 4 is a bit confusing.

I'm very interested in seeing support for stack/context switching in LLVM, if only for prototyping language ideas. I'm particularly interested in mechanisms that would make it possible to implement full asymmetric coroutines as described in "Revisiting Coroutines" (Moura & Ierusalimschy, Feb 2009 TOPLAS). From skimming the thread and looking at the llvm-stack-switch wiki, it

(Dropped llvm-dev by accident. Putting it back) HI Eli: >> coro.barrier() doesn't work: if the address of the alloca doesn't escape, >> alias analysis will assume the barrier can't read or write the value of >> the alloca, so the barrier doesn't actually block code movement. Got it. I am new to this and learning a lot over the course of this thread. Thank you

That all makes sense. I don't think the name "synthetic" is all that intuitive, though. Enum attributes are pretty cheap, maybe we should try to use a name closer to what we're trying to implement? For example, we could add a new "coroutine_foo" attribute for every coroutine style we implement. We would have analysis helper functions to answer questions like "is

Hello all! (+cc Vedant Kumar, who I've been told knows a lot about UBSan!) I am trying to fix an assert that occurs when the transforms in llvm/lib/Transforms/Coroutines are applied to LLVM IR that has been generated with UBSan enabled -- specifically, '-fsanitize=null'. You can see an example of the assert in this 26-line C++ file here: https://godbolt.org/g/Gw9UZq Note that

On Wed, Aug 05, 2020 at 04:49:04PM +0300, Nir Soffer wrote: > I see, can change the python plugin to support multiple connections to imageio > using SERIALIZE_REQUESTS? > > The GiL should not limit us since the GIL is released when you write to > imageio socket, and this is likely where the plugin spends most of the time. It's an interesting question and one I'd not really

Hi David: >> How do you deal with basic blocks which appear to be used by multiple parts >> of the coroutine? We handled this in WinEHPrepare by cloning any BBs which >> were shared. I experimented with several approaches, but, cloning ended up being the simplest and most reliable. Suspend points express three different control flows that can happen at the suspend point: a

> On Mar 19, 2018, at 3:44 PM, Brian Gesiak <modocache at gmail.com> wrote: > > Hello all! > (+cc Vedant Kumar, who I've been told knows a lot about UBSan!) > > I am trying to fix an assert that occurs when the transforms in llvm/lib/Transforms/Coroutines are applied to LLVM IR that has been generated with UBSan enabled -- specifically, '-fsanitize=null'. >

Hi all: I've included below a brief description of coroutine related optimization passes and some questions/thoughts related to them. Looking forward to your feedback, comments and questions. Thank you! Roadmap: ======== 1) Get agreement on coroutine representation and overall direction. .. repeat 1) until happy http://lists.llvm.org/pipermail/llvm-dev/2016-June/100838.html (Initial)