Linus> The system call entry becomes a simple
Linus> call *%gs:constant-offset
Linus> Not mmap. No magic system calls. No relinking. Not
Linus> _nothing_. One instruction, that's it.
I presume *%gs:0x18 is only for shared objects?
A naïve:
- asm volatile("call 0xffffe000"
+ asm volatile("call *%%gs:0x18"
in the trivial getppid benchmark code gives a SEGV, since
(according to gdb's info all-registers) %gs == 0 when it runs.
Is it just that my glibc is too old, or is there a shared vs static difference?
-JimC
P.S. On a (1 Gig) mobile p3 the getppid bench gives ~333 cycles for
int $0x80 and ~215 for call 0xffffe000, before yesterday's push.
-
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This archive was generated by hypermail 2b29 : Mon Dec 23 2002 - 22:00:30 EST