On Tue, Mar 20, 2018 at 3:32 PM, Rahul Lakkireddy <rahul.lakkire...@chelsio.com> 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? -- With Best Regards, Andy Shevchenko
