From: Linus Torvalds <[EMAIL PROTECTED]> Date: Mon, 20 Aug 2007 22:46:47 -0700 (PDT)
> Ie a "barrier()" is likely _cheaper_ than the code generation downside > from using "volatile". Assuming GCC were ever better about the code generation badness with volatile that has been discussed here, I much prefer we tell GCC "this memory piece changed" rather than "every piece of memory has changed" which is what the barrier() does. I happened to have been scanning a lot of assembler lately to track down a gcc-4.2 miscompilation on sparc64, and the barriers do hurt quite a bit in some places. Instead of keeping unrelated variables around cached in local registers, it reloads everything. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
