On Thu, 2018-11-08 at 18:01 +0000, Nikunj Kela (nkela) wrote: > CAUTION: This email originated from outside of the organization. Do not click > links or open attachments unless you recognize the sender and know the > content is safe. > > > On 11/8/18, 12:12 AM, "David Woodhouse" <dw...@infradead.org> wrote: > > On Wed, 2018-11-07 at 19:14 +0100, Richard Weinberger wrote: > > On Wed, Nov 7, 2018 at 7:05 PM Nikunj Kela (nkela) <nk...@cisco.com> > wrote: > > > I had tried to use configs to start with via the following patch > however I was advised to have a mount option: > > > > http://lists.infradead.org/pipermail/linux-mtd/2018-November/085126.html > > > > Just show performance numbers on how your implementation has an impact > or not. > > So far your implementation is also not much optimized, maybe likely() > > or static keys can help... > > Using likely() for the native case might help. Static keys might help a > little more, but could only work if every file system has the *same* > endianness. Unless we end up with three variants, for native vs. swap > vs. runtime checking. > > We also lose a bunch of the optimisations that we gained from using > __builtin_swab functions, which let the compiler see what was going on. > > But we can hypothesise and handwave about it until the cows come home; > I'd like to see a real test of whether it actually makes a difference > that we care about. > > If it does, one option might be to just build separate versions of > scan.c for each endianness, since that's the critical path we care > about. > > I wonder if this feature is really that important that we need to duplicate > the drivers. > Also, it might take some time for me to find some device that I can run the > tests with and without this patch. > I am wondering if we can still consider my first patch with config options as > a good compromise on it?
I think that is a good idea. Jocke
