On Fri, 2015-03-20 at 14:34 +0530, Anshuman Khandual wrote: > On 03/19/2015 10:13 AM, Sam Bobroff wrote: > > This patch changes the syscall handler to doom (tabort) active > > transactions when a syscall is made and return immediately without > > performing the syscall. > > > > Currently, the system call instruction automatically suspends an > > active transaction which causes side effects to persist when an active > > transaction fails. > > > > This does change the kernel's behaviour, but in a way that was > > documented as unsupported. It doesn't reduce functionality because > > syscalls will still be performed after tsuspend. It also provides a > > consistent interface and makes the behaviour of user code > > substantially the same across powerpc and platforms that do not > > support suspended transactions (e.g. x86 and s390). > > > > Performance measurements using > > http://ozlabs.org/~anton/junkcode/null_syscall.c > > indicate the cost of a system call increases by about 0.5%. > > Performance test results verified which shows an improvement of > around ~0.52% with the patch compared to without it. > > [With patch] null_syscall: 757.59 cycles 100.00% > [Without patch]] null_syscall: 753.66 cycles 100.00%
No that's a performance *decrease* with the patch applied. ? cheers _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
