Cloud Haskell and network latency issues with -threaded

[Andreas Voellmy]

Hi Edsko,

Can you explain the figure linked to on that page a bit? E.g. how should
the axes be labelled?


On Wed, Feb 6, 2013 at 9:33 AM, Edsko de Vries <edsko at well-typed.com> wrote:

> Hi,
>
> Just for clarity's sake (as the author of that "Latency" section that Tim
> referred to): I have addressed all of the issues listed there in
> Network.Transport.TCP, with the exception of the first (the -threaded
> issue). As Tim points out, this is not a Cloud Haskell specific issue; I
> have written this up as a short blog post at
> http://www.edsko.net/2013/02/06/performance-problems-with-threaded .
>
> Edsko
>
>
>
> On Wednesday, 6 February 2013 14:09:22 UTC, Tim Watson wrote:
>
>> Hi Kostirya,
>>
>> I'm putting the parallel-haskell and ghc-users lists on cc, just in case
>> other (better informed) folks want to chip in here.
>>
>> ----
>>
>> First of all, I'm assuming you're talking about network latency when
>> compiling with -threaded - if not I apologise for misunderstanding!
>>
>> There is apparently an outstanding network latency issue when compiling
>> with -threaded, but according to a conversation I had with the other
>> developers on #haskell-distributed, this is not something that's specific
>> to Cloud Haskell. It is something to do with the threaded runtime system,
>> so would need to be solved for GHC (or is it just the Network package!?) in
>> general. Writing up a simple C program and equivalent socket use in Haskell
>> and comparing the latency using -threaded will show this up.
>>
>> See the latency section in http://haskell-distributed.**github.com/wiki/*
>> *networktransport.html<http://haskell-distributed.github.com/wiki/networktransport.html>for some more details. According to that, there *are* some things we might
>> be able to do, but the 20% latency isn't going to change significantly on
>> the face of things.
>>
>> We have an open ticket to look into this (https://cloud-haskell.**
>> atlassian.net/browse/NTTCP-4<https://cloud-haskell.atlassian.net/browse/NTTCP-4>)
>> and at some point we'll try and put together the sample programs in a
>> github repository (if that's not already done - I might've missed previous
>> spikes done by Edsko or others) and investigate further.
>>
>> One of the other (more experienced!) devs might be able to chip in and
>> proffer a better explanation.
>>
>> Cheers,
>> Tim
>>
>>
>> On 6 Feb 2013, at 13:27, kost... at gmail.com wrote:
>>
>> > Haven't you had a necessity to launch Haskell in no-threaded mode
>> during the intense network data exchange?
>> > I am getting the double performance penalty in threaded mode. But I
>> must use threaded mode because epoll and kevent are available in the
>> threaded mode only.
>> >
>>
>> [snip]
>>
>> >
>> >
>> > среда, 6 февраля 2013 г., 12:33:36 UTC+2 пользователь Tim Watson
>> написал:
>> > Hello all,
>> >
>> > It's been a busy week for Cloud Haskell and I wanted to share a few of
>> > our news items with you all.
>> >
>> > Firstly, we have a new home page at http://haskell-distributed.**
>> github.com <http://haskell-distributed.github.com>,
>> > into which most of the documentation and wiki pages have been merged.
>> Making
>> > sassy looking websites is not really my bag, so I'm very grateful to
>> the
>> > various author's whose Creative Commons licensed designs and layouts
>> made
>> > it easy to put together. We've already had some pull requests to fix
>> minor
>> > problems on the site, so thanks very much to those who've contributed
>> already!
>> >
>> > As well as the new site, you will find a few of us hanging out on the
>> > #haskell-distributed channel on freenode. Please do come along and join
>> in
>> > the conversation.
>> >
>> > We also recently split up the distributed-process project into separate
>> > git repositories, one for each component that makes up Cloud Haskell.
>> This
>> > was done partly for administrative purposes and partly because we're in
>> the
>> > process of setting up CI builds for all the projects.
>> >
>> > Finally, we've moved from Github's issue tracker to a hosted
>> Jira/Bamboo setup
>> > at https://cloud-haskell.**atlassian.net<https://cloud-haskell.atlassian.net>- pull requests are naturally still welcome
>> > via Github! Although you can browse issues freely without logging in,
>> you will
>> > need to provide an email address and get an account in order to submit
>> new ones.
>> > If you have any difficulties logging in, please don't hesitate to
>> contact me
>> > directly, via this forum or the cloud-haskell-developers mailing list
>> (on
>> > google groups).
>> >
>> > As always, we'd be delighted to hear any feedback!
>> >
>> > Cheers,
>> > Tim
>>
>>  --
> You received this message because you are subscribed to the Google Groups
> "parallel-haskell" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to parallel-haskell+unsubscribe at googlegroups.com.
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/glasgow-haskell-users/attachments/20130206/749c519e/attachment.htm>