Greeting,

FYI, we noticed a -6.9% regression of will-it-scale.per_thread_ops due to commit:


commit: e585513b76f7b05d08ca3fb250fed11f6ba46ee5 ("x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

in testcase: will-it-scale
on test machine: qemu-system-x86_64 -enable-kvm -cpu host -smp 4 -m 5G
with following parameters:

	test: futex2

test-description: Will It Scale takes a testcase and runs it from 1 through to n parallel copies to see if the testcase will scale. It builds both a process and threads based test in order to see any differences between the two.
test-url: https://github.com/antonblanchard/will-it-scale



Details are as below:
-------------------------------------------------------------------------------------------------->


To reproduce:

        git clone https://github.com/01org/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script  # job-script is attached in this email

testcase/path_params/tbox_group/run: will-it-scale/futex2/vm-lkp-a03

6c690ee1039b251e  e585513b76f7b05d08ca3fb250  
----------------  --------------------------  
         %stddev      change         %stddev
             \          |                \  
    882247              -7%     821521        will-it-scale.per_thread_ops
     33180 ±126%     -3e+04       3507 ± 47%  latency_stats.avg.max
    171890 ±154%     -1e+05      22345 ± 66%  latency_stats.max.max



                            will-it-scale.per_thread_ops

  920000 ++-----------------------------------------------------------------+
         |                *                                                 |
  900000 ++ *.      .**. + :  .*      .*.                          .**      |
         *.*  *.*  *    *  *.*  *.*.**   *.*                     .*   :   *.*
         |       :+                         :.*                 *     :   : |
  880000 ++      *                          *  +           *   *       :.*  |
         |                                      * .*.**.*. :+ +        *    |
  860000 ++                                      *        *  *              |
         |                                                                  |
  840000 ++                                                                 |
         |              O O                 O                               |
         | OO              O O OO O O  O   O  O         O      O  O         |
  820000 O+   O O                    O   O            O   OO O  O           |
         |           OO                         OO O O                      |
  800000 ++------O-O--------------------------------------------------------+



  [*] bisect-good sample
  [O] bisect-bad  sample


Disclaimer:
Results have been estimated based on internal Intel analysis and are provided
for informational purposes only. Any difference in system hardware or software
design or configuration may affect actual performance.


Thanks,
Xiaolong