IRC logs for #openrisc Saturday, 2014-11-15

--- Log opened Sat Nov 15 00:00:29 2014
poke53282Oh man. My dynamic recompilation code starts to look really messy.  I mean really messy.  And complicated.04:05
olofkpoke53282: If you consider that messy, you don't want to see what I'm working on :)08:16
olofkDoes it work btw? Any speed improvements?08:16
poke53282olofk: Not really.16:59
poke53282This is a special case were it works more or less Ok.16:59
poke53282The fbdemo in my emulator.16:59
poke53282At the moment I work in blocks. From jump to jump.17:00
poke53282This is also the way how QEMU works.17:00
poke53282fbdemo is nice, because the major part are just logical operations and no jumps.17:02
poke53282The average length of such blocks is 6 instructions for -O2 compiled binaries.17:03
poke53282So in the normal case I get a speed reduction. And usually by a factor of 5-10 :(17:08
poke53282Chrome is the worst. IE is better.17:08
poke53282And in Firefox it works only if I remove the "use asm"; statement.17:09
poke53282Otherwise a speed gain of 4 will become a  speed lost of a factor of 2.17:09
poke53282I guess, this is some overhead to go from normal Javascript to asm.js code and back.17:10
poke53282But there shoudn't be any overhead.17:11
poke53282All in all it looks like, that the current strategy does not work. I will implement the DTLB lookup directly in the generated code. Then I can omit one function call.17:12
poke53282I am also unsure whether such generated code is compiled or just interpreted.17:13
poke53282Again a lot of hidden complexity of the Javascript engines, which makes is so unpredictable.17:14
poke53282But at least one good message. Firefox crashed only once yesterday ;)17:14
poke53282To be successful with this dynamic recompilation, I have to increase the code size translated. That means including jumps. But on this level there are a lot of problems to solve. There is a reason why QEMU is not doing it directly.17:58
poke53282I guess in the end I have to recompile whole functions.17:59
poke53282But then Firefox might be a real rocket.18:01
poke53282I hope this reply was sufficient olofk ;)18:08
rooi-oogwhy gnome sucks?19:47
-!- Netsplit *.net <-> *.split quits: rah, blueCmd, poke53282, knz_, fotis2, mithro, Amadiro20:05
-!- rah_ is now known as rah21:29
--- Log closed Sun Nov 16 00:00:30 2014

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