On 04/01/2015 10:51 AM, Ingo Molnar wrote: > > * Denys Vlasenko <dvlas...@redhat.com> wrote: > >> This mimics the recent similar 64-bit change. >> Saves ~110 bytes of code. >> >> Patch was run-tested on 32 and 64 bits, Intel and AMD CPU. >> I also looked at the diff of entry_64.o disassembly, to have >> a different view of the changes. > > The other important question would be: what performance difference (if > any) did you observe before/after the change?
I did not measure it then. At the moment I don't have AMD CPUs here, cant benchmark 32-bit syscall-based codepath. On a Sandy Bridge CPU (IOW: sysenter codepath) - Before: 78.57 ns per getpid After: 76.90 ns per getpid It's better than I thought it would be. Probably because this load: movl ASM_THREAD_INFO(TI_sysenter_return, %rsp, 0), %r10d has been moved up by the patch (happens sooner). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
