Hi Erik; It doesn't look like your updated classlists were pushed and I note that 'HashMap$Entry' has been renamed to 'HashMap$Node'. Are there plans to update the classlists before Java 8 is finalized? This does seem like something where "mostly right" could be worse than having no list at all.
Mike On Oct 1 2013, at 03:30 , Erik Joelsson <erik.joels...@oracle.com> wrote: > Hello again, > > I have now regenerated the classlists @b107 and run new comparisons. To me it > looks like the differences are essentially non existant between new and old > classlists and in the previous comparison we saw no difference between random > order and old classlists. > > It's very possible that it has an impact on cold starts, as Staffan suggests, > but we have no way (that I know of) of measuring that, and is that really a > valid requirement if we can't measure it? > > /Erik > > On 2013-08-20 03:54, David Holmes wrote: >> Hi Erik, >> >> Adding in hotspot-runtime-dev. >> >> There is a lot of history here and I'm not sure who remembers all the >> details - if anyone. There are existing open bugs to re-assess the utility >> of the jarreorder (7032729) and to update the classlists (8005688). >> >> David >> ------ >> >> On 20/08/2013 1:17 AM, Erik Joelsson wrote: >>> Hello, >>> >>> I wonder if anyone knows more about the jarreorder tool and why we use it? >>> >>> As I understand it, we have precalculated classlists for each platform >>> (most likely outdated) and the tool is used to make sure those classes >>> end up in a specific order, last in rt.jar. I assume this is some kind >>> of startup time optimization. >>> >>> I got some help from Claes in the performance team and did a quick run >>> of a startup and footprint benchmark, comparing a build with the rt.jar >>> reordered as normal and one where I simply turned off this feature and >>> let the files end up in the default order. Our preliminary findings show >>> that any difference between the two is negligible. Before we declare it >>> useless, we might need to test with freshly generated classlists? Does >>> anyone know how to generate them? Is there some other benefit of this >>> that I might have missed? >>> >>> I would like to propose removing jarreorder to simplify the build. This >>> would also enable faster incremental builds of the images target, by not >>> having to rebuild the whole rt.jar every time. >>> >>> /Erik >
