Hotspot at Last
Andrew C. Greenberg
werdna at gate.net
Wed Apr 28 00:38:32 UTC 1999
Sun announced the actual, really, truly, gonna-do-it-this-time,
really, uh-huh, not-kidding-at-all, this-is-it release of Hotspot, at
last. Well, sort of. (Binaries will be around "later this week" for
some platforms)
But the press release, white paper and data sheet, those are ready
for downloading right now, and they are available in fully
human-readable open-source English! (Impressive, since the
announcement was made in Paris.)
<Tongue surgically removed from cheek>
All kidding aside, it will be nice to see a serious, commercial
dynamic optimization finally hit the decks. Unsurprisingly, Sun is
already downplaying expectations, suggesting that Hotspot will be
more significant on the server side than the client side, at least on
the first release. (Quite true, since the server is likely to stay
"warm" longer.)
I did find the following bullet points in the white paper very
amusing. It appears that Sun has discovered that the following
tricks, in addition to its admittedly way-cool dynamic profiling and
adaptive optimizing, can lead to improved peformance in a VM:
(*) Handle-less pointers;
(*) Shorter (two-word) object handles;
(*) Generational, copying compacting garbage collection,
which they repeatedly characterize as "pauseless;" and
<<YOU GOTTA LOVE THIS!>>
(*) Reflective Data (Classes, MetaClasses and Methods) are
now represented as first-class objects to facilitate a simpler object
memory model and faster garbage collection.
I also thought these ideas were pretty cool . . . when I read about
them in "Back to the Future."
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