Greeting,

FYI, we noticed a -10.0% regression of blogbench.read_score due to commit:


commit: 5c279bd9e40624f4ab6e688671026d6005b066fa ("scsi: default to scsi-mq")
https://git.kernel.org/cgit/linux/kernel/git/jejb/scsi.git misc

in testcase: blogbench
on test machine: 16 threads Intel(R) Xeon(R) CPU D-1541 @ 2.10GHz with 8G memory
with following parameters:

	disk: 1SSD
	fs: ext4
	cpufreq_governor: performance

test-description: Blogbench is a portable filesystem benchmark that tries to reproduce the load of a real-world busy file server.
test-url: https://www.pureftpd.org/project/blogbench


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


To reproduce:

        git clone https://github.com/01org/lkp-tests.git
        cd lkp-tests
        bin/lkp install job.yaml  # job file is attached in this email
        bin/lkp run     job.yaml

testcase/path_params/tbox_group/run: blogbench/1SSD-ext4-performance/lkp-bdw-de1

6d311fa7d2c18659  5c279bd9e40624f4ab6e688671  
----------------  --------------------------  
         %stddev      change         %stddev
             \          |                \  
    292048             -10%     262860        blogbench.read_score
      6628 ±  4%        50%       9913 ±  4%  blogbench.write_score
    104681             319%     439016        blogbench.time.involuntary_context_switches
 1.178e+08             -27%   86266452        blogbench.time.file_system_inputs
   3112606              -8%    2877831        blogbench.time.voluntary_context_switches
       209                         214        blogbench.time.percent_of_cpu_this_job_got
       603                         620        blogbench.time.system_time
  80955370              37%   1.11e+08        blogbench.time.file_system_outputs
    193975             -27%     141449        vmstat.io.bi
    152861              35%     205958        vmstat.io.bo
     24997             124%      56094        vmstat.system.cs
     33317               7%      35633        vmstat.system.in
    428.54 ± 10%       -30%     300.32 ±  8%  iostat.sda.rrqm/s
      9670             -28%       6988        iostat.sda.r/s
    193974             -27%     141449        iostat.sda.rkB/s
    172120              31%     225064        iostat.sda.wkB/s
   8583.63               4%    8896.15        iostat.sda.wrqm/s
      6074              77%      10748        iostat.sda.w/s
   7593732             125%   17107441        perf-stat.context-switches
  21914349 ±  3%        24%   27154223 ±  4%  perf-stat.dTLB-store-misses
 3.952e+11               8%   4.27e+11        perf-stat.dTLB-loads
 2.524e+11               7%  2.701e+11        perf-stat.branch-instructions
 4.634e+10               6%  4.892e+10        perf-stat.cache-references
 1.468e+09              11%  1.627e+09        perf-stat.branch-misses
 4.634e+10               6%  4.892e+10        perf-stat.cache-misses
 1.314e+12               8%  1.425e+12        perf-stat.instructions
 2.289e+08              25%   2.86e+08 ±  4%  perf-stat.iTLB-loads
 2.279e+08              15%  2.632e+08 ±  3%  perf-stat.dTLB-load-misses
      0.06               7%       0.06        perf-stat.dTLB-load-miss-rate%
      0.59              10%       0.65        perf-stat.ipc
      0.01 ±  3%        13%       0.01 ±  4%  perf-stat.dTLB-store-miss-rate%
 2.291e+11               9%  2.503e+11        perf-stat.dTLB-stores
      0.58               4%       0.60        perf-stat.branch-miss-rate%
    285094              22%     346640        perf-stat.cpu-migrations



                                blogbench.write_score

  12000 ++------------------------------------------------------------------+
        |                                                                   |
  11000 ++                             O                                    |
        | O O     O        O O  O O       O                                 |
        O       OO  O  O                                                    |
  10000 ++   O O   O O    O    O O O  O    O                                |
        |O O            O   O O      O  OO                                  |
   9000 ++                                                                  |
        |             O                                                     |
   8000 ++                                                                  |
        |                                                                   |
        |                                                                   |
   7000 ** ***.* ****      *     ***.*** ***  * .***     *      *   **. ** **
        | *     *    ****.* *****       *   ** *    ***** *.**** ***   *  ::|
   6000 ++----------------------------------------------------------------*-+


  [*] 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