Gentoo Archives: gentoo-dev

From: Alexandre Rostovtsev <tetromino@g.o>
To: gentoo-dev@l.g.o
Subject: Re: [gentoo-dev] RFC: new global USE flag: jit
Date: Sat, 19 May 2012 10:20:58
Message-Id: 1337422795.817.4.camel@rook
In Reply to: [gentoo-dev] RFC: new global USE flag: jit by Alexandre Rostovtsev
On Mon, 2012-05-14 at 14:05 -0400, Alexandre Rostovtsev wrote:
> I propose adding the following global USE flag: > > jit - Enable just-in-time compilation for improved performance. May > prevent use of some PaX memory protection features in Gentoo Hardened. > > > Current local flags that could probably be unified: > > app-arch/libzpaq:jit - Enable just-in-time compilation for faster > compression (requires SSE2) > > dev-libs/libpcre:jit - Enable Just-In-Time compilation of regexp > bytecode to machine code, through the SLJIT compiler. This feature might > conflict wtih security mitigation strategies such as NX/PaX as enabled > by Gentoo Hardened. > > dev-python/pypy:jit - Enable the JIT compiler > > dev-scheme/racket:jit - Enable just-in-time compiler > > media-sound/csound:luajit - Use the lua just-in-time compiler > dev-lang/luajit instead of dev-lang/lua > > net-libs/webkit-gtk:jit - Enable JIT javascript compiler (disabling it > will cause performance penalty) > > www-client/epiphany:jit - Allow using net-libs/webkit-gtk that has the > JIT javascript compiler enabled > > www-client/luakit:luajit - Use the lua just-in-time compiler > dev-lang/luajit instead of dev-lang/lua, which should make luakit > faster. > > www-client/seamonkey:methodjit - Enable JIT for JavaScript using > MethodJIT for faster JS performance. Hardened users can disable this > USE-flag to use MPROTECT on grsecurity kernels. > > www-servers/nginx:pcre-jit - Enable JIT for pcre > > x11-libs/qt-core:jit - Enables JIT for Javascript usage inside Qt > > x11-libs/qt-script:jit - Enables JIT for Javascript usage inside Qt > > x11-libs/qt-webkit:jit - Enable JavaScriptCore just-in-time compiler for > faster JavaScript execution > > -Alexandre.
Update: since the response to the proposal was favorable, jit has now been added to use.desc. Two packages, webkit-gtk and epiphany, have switched to the global flag already; bugs (#416601, #416603, #416605, #416607, #416609, #416611) have been filed with maintainers of the other packages most likely to benefit from the new flag. -Alexandre.