RFR: 8253920: Share method trampolines in CDS dynamic archive
Yumin Qi
minqi at openjdk.java.net
Mon Oct 26 18:55:18 UTC 2020
On Mon, 26 Oct 2020 18:12:16 GMT, Calvin Cheung <ccheung at openjdk.org> wrote:
> This patch is to allow sharing of the same method trampoline for archived Methods with the same AdapterHandleEntry when using CDS dynamic archive.
>
> Running javac on HelloWorld with CDS dynamic archive, the number of calls to SharedRuntime::generate_trampoline() is reduced to 406 times vs 12601 times without the patch.
>
> In terms of saving on instructions and time (on linux-x64):
> instr delta = -2807662 -0.1369%
> time delta = -6.860 ms -1.8798%
>
> It passed tiers 1,2,3,4 testing.
Looks good. Minor suggestions.
src/hotspot/share/memory/archiveBuilder.cpp line 896:
> 894: for (int i = 0; i < klasses()->length(); i++) {
> 895: Klass* k = klasses()->at(i);
> 896: if (!k->is_instance_klass()) {
Could you use
if (k->is_instance_klass()) {
...
}
as same style of line 869
src/hotspot/share/oops/method.cpp line 1111:
> 1109:
> 1110: assert(_from_compiled_entry != NULL, "sanity");
> 1111: if (DumpSharedSpaces) {
I think you can remove this if check.
-------------
Marked as reviewed by minqi (Reviewer).
PR: https://git.openjdk.java.net/jdk/pull/868
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