Re: Meaning of -i and -hidir

The behavior of `-hidir` and `-i` changed in response to this issue: https://gitlab.haskell.org/ghc/ghc/-/issues/16500 We just ran into this and I think the change is unfortunate. I don't think `-hidir` (a flag about output) should override the input search flag. I would like it to at least

Re: Fwd: Restricted sums in BoxedRep

something else. On Thu, Oct 15, 2020 at 4:27 PM Carter Schonwald wrote: > Ryan: would an unboxed value Mvar, Eg to write StrictMvar (), avoid > creating extra gc pressure / traversal a? > > On Thu, Oct 15, 2020 at 4:23 PM Ryan Yates wrote: > >> Ah yes. In my research wo

Re: Fwd: Restricted sums in BoxedRep

ntages to cutting out the extra heap objects. > > On Thu, Oct 15, 2020, 1:10 PM Ryan Yates wrote: > >> I haven't been following this discussion too closely, but in my research >> work I found that some of the benefits that I wanted in this direction were >> already there w

Re: Fwd: Restricted sums in BoxedRep

I haven't been following this discussion too closely, but in my research work I found that some of the benefits that I wanted in this direction were already there with pointer tagging. On Thu, Oct 15, 2020 at 12:59 PM David Feuer wrote: > Yes, that's something quite different. We'd need a whole

Re: GHC Logo

Cats are warm and fuzzy. On Wed, Sep 2, 2020 at 10:38 AM Richard Eisenberg wrote: > On Sep 2, 2020, someone wrote to me privately saying: > > > I was thinking Cats for some reason. > > Ooh. I'm picturing a cat with its tail wrapped around a lambda, or > something like that. And Simon PJ does

Re: Wiki markup

Hi Simon, I think you can just indent the code block to achieve this. Ryan On Mon, Jun 3, 2019 at 12:46 PM Simon Peyton Jones via ghc-devs < ghc-devs@haskell.org> wrote: > This is a GitLab wiki markup question. > > Suppose I want to have a bulleted list, in which a single item has some > text,

Re: MutVar# and GC

Hi, Because GHC's GC is generational it needs a way to handle heap objects from older generations that point into younger generations. This only happens when an older object is mutated to point to a younger object. GHC solves this by invoking the GC write barrier (not to be confused with write

Re: Use NULL instead of END_X_QUEUE closures?

Hi Ömer, These are pointed to by objects traversed by GC. They have info tables like any other heap object that GC can understand. I think this is a much simpler invariant to hold then to have some heap objects point to NULL. Ryan On Mon, May 7, 2018 at 3:34 PM, Ömer Sinan Ağacan

Re: Where to raise an issue for the stm library

Hi Harendra, I think STM issues are fine to report to GHC's trac (please someone else chime in if this isn't the case): https://ghc.haskell.org/trac/ghc/wiki/ReportABug If that isn't the appropriate place it can get sorted out from there. Ryan On Fri, Aug 25, 2017 at 3:06 PM, Harendra Kumar

Re: NCG lowering of sqrt

Hi Kavon, I looked a bit and it does not appear that there is an SSE sqrt in the native code gen. It should be easy to add (see a similar addition here: https://phabricator.haskell.org/D3265). The x87 version was available for 32-bit. I think if you use the LLVM backend it will give you the

Re: DeriveFoldable treatment of tuples is surprising

Thanks for the clarification! Ryan On Wed, Mar 22, 2017 at 9:47 AM, Ryan Scott wrote: > I believe what Sven was saying is not that the Foldable instance for > tuples are given "special treatment" (which is arguably an orthogonal > discussion), but rather that

Re: DeriveFoldable treatment of tuples is surprising

On Wed, Mar 22, 2017 at 4:12 AM, Sven Panne wrote: > 2017-03-21 22:29 GMT+01:00 Edward Kmett : > >> [... In general I think the current behavior is the least surprising as >> it "walks all the a's it can" and is the only definition compatible with >>

Re: setnumcapabilities001 failure

eleaseGCThreads while enabled_capabilities is being > changed. > > (*) well except for the parts at the boundary with the external world > which run without a capability, such as rts_lock() which acquires a > capability. > > Cheers > Simon > > On 27 Oct 2016 17:10, "Ryan

Re: setnumcapabilities001 failure

Briefly looking at the code it seems like several global variables involved should be volatile: n_capabilities, enabled_capabilities, and capabilities. Perhaps in a loop like in scheduleDoGC the compiler moves the reads of n_capabilites or capabilites outside the loop. A failed requestSync in

Re: Semantics of MVars and IORefs?

Hi Iavor, You might be interested in what Edward has written about this: http://blog.ezyang.com/2014/01/so-you-want-to-add-a-new-concurrency-primitive-to-ghc/ I would say when we do have a memory model for GHC the program you gave will almost certainly be correct. MVar operations should be

Re: Is Safe Haskell intended to allow segfaults?

Hi Ryan, I have similar concerns with safety and STM. In particular, lazy validation allows for execution after inconsistent reads from TVars. The obvious problem to avoid is falling into an infinite loop. As long as -fno-omit-yields is used (on every module?) and maybe some other conditions

Re: Temporarily pinning a thread to a capability

A thread with TSO_LOCKED can be migrated if the number of capabilities decreases. Ryan On Tue, Oct 27, 2015 at 11:35 PM, Edward Kmett wrote: > Would anything go wrong with a thread id if I pinned it to a capability > after the fact? > > I could in theory do so just by setting

Re: Temporarily pinning a thread to a capability

ly on an invariant that setNumCapabilities is > called before you spin up these Par-like computations. > > -Edward > > On Wed, Oct 28, 2015 at 4:28 PM, Ryan Yates <fryguy...@gmail.com> wrote: > >> A thread with TSO_LOCKED can be migrated if the number of capabilities >>

Re: Unlifted data types

https://ghc.haskell.org/trac/ghc/wiki/UnliftedDataTypes On Thu, Oct 8, 2015 at 6:02 AM, Simon Peyton Jones wrote: > | I've added a section on parametric levity polymorphism to the wiki. > | Sorry it took so long. > > What's the wiki page? > > Simon > | > | I might add

Re: ArrayArrays

for someone who has graduate students lying around. Maybe somebody at Indiana University who has an interest in type theory and parallelism can find us one. =) -Edward On Fri, Aug 28, 2015 at 8:48 PM, Ryan Yates fryguy...@gmail.com wrote: I think from my perspective, the motivation

Re: ArrayArrays

of MutableStruct# with a known number of words and a known number of pointers is basically what Ryan Yates was suggesting above, but where the word counts were stored in the objects themselves. Given that it'd have a couple of words for those counts it'd likely want to be something we build

Re: ArrayArrays

Hi Edward, I've been working on removing indirection in STM and I added a heap object like SmallArray, but with a mix of words and pointers (as well as a header with metadata for STM). It appears to work well now, but it is missing the type information. All the pointers have the same type which

Re: Can we fix our Trac that doesn't lose new ticket text

My very pessimistic rule of thumb is don't trust a form field unless the site actively saves a draft as you type. On Fri, Apr 24, 2015 at 10:13 AM, Eric Crockett ecrocke...@gmail.com wrote: My Firefox also has this issue. So it seems the problem is the browser itself. How can this be fixed on

Re: STM and GC write barrier

Ok, that explains it. Thanks! On Thu, Nov 6, 2014 at 7:34 AM, Simon Marlow marlo...@gmail.com wrote: On 15/09/2014 17:50, Ryan Yates wrote: I'm starting to get to the bottom of something that has been puzzling me for a while. Recently commit 6d784c43592290ec16db8b7f0f2a012dff3ed497 [1

STM and GC write barrier

Hi All, I'm starting to get to the bottom of something that has been puzzling me for a while. Recently commit 6d784c43592290ec16db8b7f0f2a012dff3ed497 [1] introduced the GC write barrier for TVars. Not fully understanding things and reading the commit message to be saying that this was an

Re: Possible bug related to stm and exceptions

The bug that Luite and I uncovered is http://ghc.haskell.org/trac/ghc/ticket/7930. It would not be related. There was a bug relating to `catchSTM` that was fixed recently: http://ghc.haskell.org/trac/ghc/ticket/8035. And another related to profiling: http://ghc.haskell.org/trac/ghc/ticket/8298.

Re: STM Commentary

Research Limited (company number 03369488) is registered in England and Wales* *Registered office 21 Station Road, Cambridge, CB1 2FB *** ** ** *From:* ghc-devs-boun...@haskell.org [mailto:ghc-devs-boun...@haskell.org] *On Behalf Of *Ryan Yates *Sent:* 17 May 2013 21:06 *To:* ghc-devs

STM Commentary

appropriate. If anyone has opinions on that, let me know. Any comments are welcome, it may be easiest to just comment on the source directly on Github, but I will, of course, take feedback in any form. Thanks, Ryan Yates ___ ghc-devs mailing list ghc-devs

Re: STM Commentary

On Fri, May 17, 2013 at 4:19 PM, Ian Lynagh i...@well-typed.com wrote: Why not put it on http://hackage.haskell.org/trac/ghc/wiki/Commentary/Rts/STM ? If you sign up for an account on the trac then you should be able to edit that page. Sure, I wanted to make sure that anyone who wanted