Re: [webkit-dev] Potential problem with member function pointer sizes
Hi Chris, I wonder whether what you have reported would cause this issue: https://bugs.webkit.org/show_bug.cgi?id=151162 Cheers, Isaac On 14 April 2016 at 09:17, Vienneau, Christopher wrote: > Hi, > > > > I just wanted to give a heads up on an issue I recently investigated, the > details can be seen in this forums post: > > > https://social.msdn.microsoft.com/Forums/vstudio/en-US/72343dd4-3a43-46e8-889e-73dc4d8e9432/discrepancy-with-sizeof-in-template?forum=vcgeneral > > The short version is that the MSVC compiler will do the wrong then when > making a member function pointer to a class that it only has a forward > declaration for. This can be fixed by either providing the definition for > the class or by using the /vmg compiler flag. > > > > I did not experience this problem with Apples WinCairo sample, but I > suspect it could happen. > > > > Chris Vienneau > > ___ > webkit-dev mailing list > webkit-dev@lists.webkit.org > https://lists.webkit.org/mailman/listinfo/webkit-dev > > ___ webkit-dev mailing list webkit-dev@lists.webkit.org https://lists.webkit.org/mailman/listinfo/webkit-dev
[webkit-dev] Potential problem with member function pointer sizes
Hi, I just wanted to give a heads up on an issue I recently investigated, the details can be seen in this forums post: https://social.msdn.microsoft.com/Forums/vstudio/en-US/72343dd4-3a43-46e8-889e-73dc4d8e9432/discrepancy-with-sizeof-in-template?forum=vcgeneral The short version is that the MSVC compiler will do the wrong then when making a member function pointer to a class that it only has a forward declaration for. This can be fixed by either providing the definition for the class or by using the /vmg compiler flag. I did not experience this problem with Apples WinCairo sample, but I suspect it could happen. Chris Vienneau ___ webkit-dev mailing list webkit-dev@lists.webkit.org https://lists.webkit.org/mailman/listinfo/webkit-dev
Re: [webkit-dev] BigO correlation tests
> On Apr 13, 2016, at 12:18 PM, Ryosuke Niwa wrote: > > I think Darin likes these tests. I love the idea of them and I’d like to see us write more. Changing our algorithms to be efficient for large data sets is a tricky problem and an easy way to write a test that cleanly checks for that is quite valuable. Not sure if they specific way they are currently implemented realizes the potential of this type of test. — Darin ___ webkit-dev mailing list webkit-dev@lists.webkit.org https://lists.webkit.org/mailman/listinfo/webkit-dev
Re: [webkit-dev] BigO correlation tests
On Wed, Apr 13, 2016 at 12:17 AM, Nikos Andronikos wrote: > >> >> However, what you proposed will only reduce the likelihood of type I errors >> (false positives). You should also examine how it affects the likelihood of >> type II errors (false negative). You might want to make some API >> artificially O(n^2) and make sure the test starts failing, etc… > > That’s a fair comment (regarding false negatives), we can do that. But to be > honest, I don’t have a lot of faith in the reliability of these tests anyway. > Since they were added by Google, do you have any thoughts on whether we could > remove them? If they never pass anywhere, then removing them seems okay although other contributors may have opposing views. e.g. I think Darin likes these tests. +darin to that end. >> You can probably look at the svn/git blame the change which added relevant >> tests in LayoutTests/perf/ and apply a reverse change locally to test that. > > Sorry, I’m not following what you’re saying here. I think some of these tests are added as a part of patch to fix a performance issue. e.g. http://trac.webkit.org/browser/trunk/LayoutTests/perf/htmlcollection-backwards-iteration.html was added in http://trac.webkit.org/changeset/122660 when I fixed HTMLCollection to be not O(n^2) four years ago. You could conceivably make HTMLCollection O(n^2), e.g. by reverting my fix, and run the test. The test should fail. Since the codebase has changed quite dramatically since I added that test so you can't probably just undo what I did. It might be easier to just add some loop that iterate over nodes instead. - R. Niwa ___ webkit-dev mailing list webkit-dev@lists.webkit.org https://lists.webkit.org/mailman/listinfo/webkit-dev
Re: [webkit-dev] BigO correlation tests
> On 13 Apr 2016, at 4:22 PM, Ryosuke Niwa wrote: > > I don’t think order of magnitudes tests ever quite worked JSC (it was added > by Google so it obviously worked on V8). If adjusting the threshold was all > that was needed to make the tests pass, I see no reason how to change it. Adjusting the threshold is one part, but we’re also improving the method by examining the slope to give a better indication of whether the test is running in constant time. > > However, what you proposed will only reduce the likelihood of type I errors > (false positives). You should also examine how it affects the likelihood of > type II errors (false negative). You might want to make some API > artificially O(n^2) and make sure the test starts failing, etc… That’s a fair comment (regarding false negatives), we can do that. But to be honest, I don’t have a lot of faith in the reliability of these tests anyway. Since they were added by Google, do you have any thoughts on whether we could remove them? > You can probably look at the svn/git blame the change which added relevant > tests in LayoutTests/perf/ and apply a reverse change locally to test that. Sorry, I’m not following what you’re saying here. Nikos The information contained in this email message and any attachments may be confidential and may also be the subject to legal professional privilege. If you are not the intended recipient, any use, interference with, disclosure or copying of this material is unauthorised and prohibited. If you have received this email in error, please immediately advise the sender by return email and delete the information from your system. ___ webkit-dev mailing list webkit-dev@lists.webkit.org https://lists.webkit.org/mailman/listinfo/webkit-dev
