Messages in this thread | | | Date | Sun, 10 Apr 2016 22:17:28 +0800 | From | Pan Xinhui <> | Subject | Re: [PATCH] powerpc: introduce {cmp}xchg for u8 and u16 |
| |
On 2016年04月08日 15:47, Peter Zijlstra wrote: > On Fri, Apr 08, 2016 at 02:41:46PM +0800, Pan Xinhui wrote: >> From: pan xinhui <xinhui.pan@linux.vnet.ibm.com> >> >> Implement xchg{u8,u16}{local,relaxed}, and >> cmpxchg{u8,u16}{,local,acquire,relaxed}. >> >> Atomic operation on 8-bit and 16-bit data type is supported from power7 > > And yes I see nothing P7 specific here, this implementation is for > everything PPC64 afaict, no? > Hello Peter, No, it's not for every ppc. So yes, I need add #ifdef here. Thanks for pointing it out. We might need a new config option and let it depend on POWER7/POWER8_CPU or even POWER9...
> Also, note that you don't need explicit 8/16 bit atomics to implement > these. Its fine to use 32bit atomics and only modify half the word. > That is true. But I am a little worried about the performance. It will forbid any other tasks to touch the other half word during the load/reserve, right? I am working on the qspinlock implementation on PPC. Your and Waiman's patches are so nice. :)
> Also, you might want to invest in some CPP to reduce the endless > repetition. > Will do that. thanks for your tips.
thanks xinhui > Other than that, no objections :-) >
| |