On Tuesday, March 03/20/18, 2018 at 19:14:46 +0530, Andy Shevchenko wrote: > On Tue, Mar 20, 2018 at 3:32 PM, Rahul Lakkireddy > <[email protected]> wrote: > > On Monday, March 03/19/18, 2018 at 20:13:10 +0530, Thomas Gleixner wrote: > >> On Mon, 19 Mar 2018, Rahul Lakkireddy wrote: > > >> Aside of that I very much doubt that this is faster than 4 consecutive > >> 64bit reads/writes as you have the full overhead of > >> kernel_fpu_begin()/end() for each access. > >> > >> You did not provide any numbers for this so its even harder to > >> determine. > >> > > > > Sorry about that. Here are the numbers with and without this series. > > > > When reading up to 2 GB on-chip memory via MMIO, the time taken: > > > > Without Series With Series > > (64-bit read) (256-bit read) > > > > 52 seconds 26 seconds > > > > As can be seen, we see good improvement with doing 256-bits at a > > time. > > But this is kinda synthetic test, right? > If you run in a normal use case where kernel not only collecting logs, > but doing something else, especially with frequent userspace > interaction, would be trend the same? >
We see same improvement when collecting logs while running heavy IO with iozone. Thanks, Rahul
