Displaying 20 results from an estimated 30000 matches similar to: "[RFC] Introducing convergence control bundles and intrinsics"
2020 Aug 17
2
[RFC] Introducing convergence control bundles and intrinsics
Hi Hal,
On Mon, Aug 17, 2020 at 2:13 AM Hal Finkel <hfinkel at anl.gov> wrote:
> Thanks for sending this. What do you think that we should do with the
> existing convergent attribute?
My preference, which is implicitly expressed in the review, is to use
`convergent` both for the new and the old thing. They are implicitly
distinguished via the "convergencectrl" operand
2020 Aug 17
2
[RFC] Introducing convergence control bundles and intrinsics
On Mon, Aug 17, 2020 at 7:14 PM Hal Finkel <hfinkel at anl.gov> wrote:
> On 8/17/20 11:51 AM, Nicolai Hähnle wrote:
> > Hi Hal,
> >
> > On Mon, Aug 17, 2020 at 2:13 AM Hal Finkel <hfinkel at anl.gov> wrote:
> >> Thanks for sending this. What do you think that we should do with the
> >> existing convergent attribute?
> > My preference, which
2020 Aug 09
2
_mm_lfence in both pathes of an if/else are hoisted by SimplfyCFG potentially breaking use as a speculation barrier
Hi Craig,
The review for the similar GPU problem is now up here:
https://reviews.llvm.org/D85603 (+ some other patches on the
Phabricator stack).
>From a pragmatic perspective, the constraints added to program
transforms there are sufficient for what you need. You'd produce IR
such as:
%token = call token @llvm.experimental.convergence.anchor()
br i1 %c, label %then, label %else
2020 Jul 28
2
_mm_lfence in both pathes of an if/else are hoisted by SimplfyCFG potentially breaking use as a speculation barrier
_mm_lfence was originally documented as a load fence. But in light of
speculative execution vulnerabilities it has started being advertised as a
way to prevent speculative execution. Current Intel Software Development
Manual documents it as "Specifically, LFENCE does not execute until all
prior instructions have completed locally, and no later instruction begins
execution until LFENCE
2019 Feb 09
1
[RFC] Adding thread group semantics to LangRef (motivated by GPUs)
On Sat, Feb 9, 2019 at 4:44 PM Jan Sjodin <jan_sjodin at yahoo.com> wrote:
> > The reason I'm looking for solutions that can work without "scanning the
> > code" or "spooky action at a distance" is that we should have a solution
> > that's easily digestible by folks who are not aware of GPU execution
> models.
> >
> > The fallback
2019 Feb 01
2
[RFC] Adding thread group semantics to LangRef (motivated by GPUs)
On 31.01.19 15:59, Jan Sjodin wrote:
>> > Any transform that re-arranges control flow would potentially have to
>> > know about the properties of ballot(), and the rules with respect to
>> > the CFG (and maybe consider the target) to know where to insert the
>> > intrinsics.
>
>> But the same is true for basically any approach to handling this. In
2019 Jan 30
2
[RFC] Adding thread group semantics to LangRef (motivated by GPUs)
On Wed, Jan 30, 2019 at 4:20 PM Jan Sjodin <jan_sjodin at yahoo.com> wrote:
>
> >
> > > > for (int i = 0; i < 2; i++) {
> > > > foo = ballot(true); // ballot 1
> > > >
> > > > if (threadID /* ID of the thread within a wavefront/warp */ % 2
> == 0) continue;
> > > >
> > > > bar = ballot(true); //
2019 Jan 31
2
[RFC] Adding thread group semantics to LangRef (motivated by GPUs)
On Wed, Jan 30, 2019 at 7:20 AM Jan Sjodin via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
>
> >
> > > > for (int i = 0; i < 2; i++) {
> > > > foo = ballot(true); // ballot 1
> > > >
> > > > if (threadID /* ID of the thread within a wavefront/warp */ % 2
> == 0) continue;
> > > >
> > > > bar =
2019 Jan 30
3
[RFC] Adding thread group semantics to LangRef (motivated by GPUs)
On Mon, Jan 28, 2019 at 9:09 PM Jan Sjodin <jan_sjodin at yahoo.com> wrote:
>
> > for (int i = 0; i < 2; i++) {
> > foo = ballot(true); // ballot 1
> >
> > if (threadID /* ID of the thread within a wavefront/warp */ % 2 == 0) continue;
> >
> > bar = ballot(true); // ballot 2
> > }
> >
> > versus:
> >
> > int i =
2019 Jan 31
3
[RFC] Adding thread group semantics to LangRef (motivated by GPUs)
Strong agree with Mehdi, I am also not really sure what is the proposal at
this point so it's hard to comment further.
> There are a number of questions that I have. Do we need better machine
descriptions so that various resources can be considered? Do we need the
capability to reason about the machine state for the cross-lane operations
to enable more optimizations? Are intrinsics the
2019 Jan 28
2
[RFC] Adding thread group semantics to LangRef (motivated by GPUs)
On Fri, Jan 25, 2019 at 3:05 AM Jan Sjodin <jan_sjodin at yahoo.com> wrote:
>
> > for (...) {
> > ballot();
> > if (... /* non-uniform */) continue;
> > }
> >
> > into
> >
> > for (...) {
> > do {
> > ballot();
> > } while (... /* non-uniform */);
> > }
>
> I'm not sure if I follow
2012 Jun 23
9
[PATCH 0/5] btrfs: lz4/lz4hc compression
WARNING: This is not compatible with the previous lz4 patchset. If you''re using
experimental compression that isn''t in mainline kernels, be prepared to backup
and restore or decompress before upgrading, and have backups in case it eats
data (which appears not to be a problem any more, but has been during
development).
These patches add lz4 and lz4hc compression
2017 Jan 18
2
[RFC] IR-level Region Annotations
> On Jan 17, 2017, at 4:36 PM, Hal Finkel via llvm-dev <llvm-dev at lists.llvm.org> wrote:
>
>
> On 01/17/2017 05:36 PM, Wael Yehia via llvm-dev wrote:
>> Hi. Regarding the token approach, I've read some documentation (review D11861, EH in llvm, and Reid and David's presentation) but couldn't answer the following question.
>> Does the intrinsic or the
2016 Oct 24
2
RFC: (Co-)Convergent functions and uniform function parameters
> On Oct 24, 2016, at 4:15 PM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
>
> On 25.10.2016 01:11, Nicolai Hähnle wrote:
>> On 24.10.2016 21:54, Mehdi Amini wrote:
>>>> On Oct 24, 2016, at 12:38 PM, Nicolai Hähnle via llvm-dev
>>>> <llvm-dev at lists.llvm.org> wrote:
>>>> Some brain-storming on an issue with SPMD/SIMT backend
2017 Jan 17
2
[RFC] IR-level Region Annotations
Hi. Regarding the token approach, I've read some documentation (review D11861, EH in llvm, and Reid and David's presentation) but couldn't answer the following question.Does the intrinsic or the instruction returning a token type object act as a code motion barrier? In other words, does it prevent other operations from being reordered with it?If the answer is no, then does it mean the
2004 Oct 05
1
constrOptim convergence
Hello, I got a question with the R function constrOptim.
>From the R help, it says that the return values of "constrOptim" are the
same as "optim". For the return value "convergence" of the function
"optim", the values should be 0, 1, 10, 51 and 52. See
http://www.maths.lth.se/help/R/.R/library/stats/html/optim.html
When I use constrOptim, I get
2019 Jan 24
3
[RFC] Adding thread group semantics to LangRef (motivated by GPUs)
I don't see how this would fix the continue vs. nested loop problem I
explained earlier. That is, how would this prevent turning:
for (...) {
ballot();
if (... /* non-uniform */) continue;
}
into
for (...) {
do {
ballot();
} while (... /* non-uniform */);
}
and vice versa? Note that there's no duplication going on here, and
the single-threaded flow of control is
2010 Jul 14
3
Convergent series
What are some reliable R functions that can compute the value of a
convergent series?
David
--
David R. Bickel, PhD
Associate Professor
Ottawa Institute of Systems Biology
Biochem., Micro. and I. Department
Mathematics and Statistics Department
University of Ottawa
451 Smyth Road
Ottawa, Ontario K1H 8M5
http://www.statomics.com
Office Tel: (613) 562-5800 ext. 8670
Office Fax: (613) 562-5185
2009 Nov 18
1
bug in '...' of constrOptim (PR#14071)
Dear all,
There appears to be a bug in how constrOptim handles ... arguments that
are suppose to be passed to optim, according to the documentation. This
means you can't get the hessian to be returned, for example (so this is
a real problem, and not just a question of mistaken documentation).
Looking at the code, it appears that a call to the user-defined f
includes the ..., when the ...
2007 Dec 13
1
convergence error code in mixed effects models
Dear All,
I want to analyse treatment effects with time series
data: I measured e.g. leaf number (five replicate
plants) in relation to two soil pH - after 2,4,6,8
weeks. I used mixed effects models, but some analyses
didn?t work. It seems for me as if this is a randomly
occurring problem since sometimes the same model works
sometimes not.
An example:
> names(test)
[1] "rep"