K 10
svn:author
V 3
kib
K 8
svn:date
V 27
2011-09-29T00:39:56.799823Z
K 7
svn:log
V 927
Merge the optimizations for the syscall entry and leave.

MFC r225474:
Inline the syscallenter() and syscallret(). This reduces the time measured
by the syscall entry speed microbenchmarks by ~10% on amd64.

MFC r225475:
Perform amd64-specific microoptimizations for native syscall entry
sequence. The effect is ~1% on the microbenchmark.

In particular, do not restore registers which are preserved by the
C calling sequence. Align the jump target. Avoid unneeded memory
accesses by calculating some data in syscall entry trampoline.

MFC r225483:
The jump target shall be after the padding, not into it.

MFC r225575:
Microoptimize the return path for the fast syscalls on amd64. Arrange
the code to have the fall-through path to follow the likely target.
Do not use intermediate register to reload user %rsp.

MFC r225576:
Put amd64_syscall() prototype in md_var.h.

Tested by:	 Alexandr Kovalenko <never nevermind kiev ua>

END