Re: [RFC 0/3] ARM: copy_{from,to}_user() for vmsplit 4g/4g

[afzal mohammed]

Hi,

On Fri, Jun 12, 2020 at 11:19:23AM -0400, Nicolas Pitre wrote:
> On Fri, 12 Jun 2020, afzal mohammed wrote:

> > Performance wise, results are not encouraging, 'dd' on tmpfs results,

> Could you compare with CONFIG_UACCESS_WITH_MEMCPY as well?

                 512     1K      4K     16K     32K     64K     1M
 
normal           30      46      89     95      90      85      65

uaccess_w_memcpy 28.5    45      85     92      91      85      65

w/ series        22      36      72     79      78      75      61

There are variations in the range +/-2 in some readings when repeated,
not put above, to keep comparison simple.

Regards
afzal