On Fri, 8 Jul 2011, Richard Henderson wrote:
I find this attitude to be short-sighted. These exact same arguments were made about a.out vs elf, and all the horrible extra overhead that elf has with its plts and dynamic symbol resolution.
The fact that people came up with hacks such as prelinking must not be for nothing.
I urge you to go ahead and create the VDSO anyway, even if you continue to bypass it with new fixed addresses for new entry points.
I have no problem with that at all. Keeping the fixed address ABI will at least provide an alternative to those who are always after the last bit of performance because they don't know better than calling get_tls() a couple thousand times per second within the same thread.
The VDSO does more than simply hold the code for those functions, it also describes them with the symbol and symbol versioning tables, and the unwind info. This is of enormous value to debugging and other introspection tools.
Absolutely.
Nicolas