On Mon, Mar 06, 2017 at 02:59:07PM +0000, David Laight wrote: > From: Peter Zijlstra > > Sent: 06 March 2017 11:22 > > To: Madhavan Srinivasan > > Cc: Wang Nan; Alexander Shishkin; linux-ker...@vger.kernel.org; Arnaldo > > Carvalho de Melo; Alexei > > Starovoitov; Ingo Molnar; Stephane Eranian; Sukadev Bhattiprolu; > > linuxppc-dev@lists.ozlabs.org > > Subject: Re: [PATCH v2 1/6] powerpc/perf: Define big-endian version of > > perf_mem_data_src > > > > On Mon, Mar 06, 2017 at 04:13:08PM +0530, Madhavan Srinivasan wrote: > > > From: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com> > > > > > > perf_mem_data_src is an union that is initialized via the ->val field > > > and accessed via the bitmap fields. For this to work on big endian > > > platforms, we also need a big-endian represenation of perf_mem_data_src. > > > > Doesn't this break interpreting the data on a different endian machine? > > Best to avoid bitfields if you ever care about the bit order.
Too late for that. But perf tool has quite a bit of code to muck fields between different endians. With the full intent that generation on one machine is readable by another.