Re: [PATCH 3/3] powerpc: bpf: implement in-register swap for 64-bit endian operations

2017-01-24 Thread 'Naveen N. Rao'
On 2017/01/24 04:13PM, David Laight wrote: > From: 'Naveen N. Rao' > > Sent: 23 January 2017 19:22 > > On 2017/01/15 09:00AM, Benjamin Herrenschmidt wrote: > > > On Fri, 2017-01-13 at 23:22 +0530, 'Naveen N. Rao' wrote: > > > > > That rather depends on whether the processor has a store to load > >

RE: [PATCH 3/3] powerpc: bpf: implement in-register swap for 64-bit endian operations

2017-01-24 Thread David Laight
From: 'Naveen N. Rao' > Sent: 23 January 2017 19:22 > On 2017/01/15 09:00AM, Benjamin Herrenschmidt wrote: > > On Fri, 2017-01-13 at 23:22 +0530, 'Naveen N. Rao' wrote: > > > > That rather depends on whether the processor has a store to load > > > > forwarder > > > > that will satisfy the read fro

Re: [PATCH 3/3] powerpc: bpf: implement in-register swap for 64-bit endian operations

2017-01-23 Thread 'Naveen N. Rao'
On 2017/01/15 09:00AM, Benjamin Herrenschmidt wrote: > On Fri, 2017-01-13 at 23:22 +0530, 'Naveen N. Rao' wrote: > > > That rather depends on whether the processor has a store to load forwarder > > > that will satisfy the read from the store buffer. > > > I don't know about ppc, but at least some x

Re: [PATCH 3/3] powerpc: bpf: implement in-register swap for 64-bit endian operations

2017-01-15 Thread Benjamin Herrenschmidt
On Fri, 2017-01-13 at 23:22 +0530, 'Naveen N. Rao' wrote: > > That rather depends on whether the processor has a store to load forwarder > > that will satisfy the read from the store buffer. > > I don't know about ppc, but at least some x86 will do that. > > Interesting - good to know that. > > H

Re: [PATCH 3/3] powerpc: bpf: implement in-register swap for 64-bit endian operations

2017-01-13 Thread 'Naveen N. Rao'
On 2017/01/13 05:17PM, David Laight wrote: > From: Naveen N. Rao > > Sent: 13 January 2017 17:10 > > Generate instructions to perform the endian conversion using registers, > > rather than generating two memory accesses. > > > > The "way easier and faster" comment was obviously for the author, not

RE: [PATCH 3/3] powerpc: bpf: implement in-register swap for 64-bit endian operations

2017-01-13 Thread David Laight
From: Naveen N. Rao > Sent: 13 January 2017 17:10 > Generate instructions to perform the endian conversion using registers, > rather than generating two memory accesses. > > The "way easier and faster" comment was obviously for the author, not > the processor. That rather depends on whether the p

[PATCH 3/3] powerpc: bpf: implement in-register swap for 64-bit endian operations

2017-01-13 Thread Naveen N. Rao
Generate instructions to perform the endian conversion using registers, rather than generating two memory accesses. The "way easier and faster" comment was obviously for the author, not the processor. Signed-off-by: Naveen N. Rao --- arch/powerpc/net/bpf_jit_comp64.c | 22 ++