Speed up jrnl by 10%, improve slow imports

[wotgl]

Hi!

I noticed, that jrnl starts with a slight delay. I researched code and found some slow and rare global imports.
I made rare imports local and added an additional function, which checks version of jrnl.

These improvements have boosted speed by 10% and have boosted python imports by 23%. I used
perf stat and python3 -X importtime for analyzing.

Perf stat on the develop branch:

[user@pc jrnl]$ echo "" > /home/user/.local/share/jrnl/journal.txt
[user@pc jrnl]$ perf stat -r 100 -d ./run test

 Performance counter stats for './run test' (100 runs):

            254,69 msec task-clock:u              #    0,993 CPUs utilized            ( +-  0,67% )
                 0      context-switches:u        #    0,000 K/sec                  
                 0      cpu-migrations:u          #    0,000 K/sec                  
             3 363      page-faults:u             #    0,013 M/sec                    ( +-  0,05% )
       377 839 305      cycles:u                  #    1,484 GHz                      ( +-  0,34% )  (60,78%)
       485 808 775      instructions:u            #    1,29  insn per cycle           ( +-  0,20% )  (74,92%)
       101 730 359      branches:u                #  399,435 M/sec                    ( +-  0,13% )  (75,89%)
         3 194 572      branch-misses:u           #    3,14% of all branches          ( +-  0,20% )  (76,18%)
       136 039 720      L1-dcache-loads:u         #  534,148 M/sec                    ( +-  0,29% )  (76,24%)
         7 853 820      L1-dcache-load-misses:u   #    5,77% of all L1-dcache hits    ( +-  0,40% )  (76,28%)
         2 254 441      LLC-loads:u               #    8,852 M/sec                    ( +-  0,62% )  (47,87%)
           399 044      LLC-load-misses:u         #   17,70% of all LL-cache hits     ( +-  2,48% )  (47,54%)

           0,25655 +- 0,00190 seconds time elapsed  ( +-  0,74% )

Perf stat with my improvements:

[user@pc jrnl]$ echo "" > /home/user/.local/share/jrnl/journal.txt
[user@pc jrnl]$ perf stat -r 100 -d ./run test

 Performance counter stats for './run test' (100 runs):

            228,56 msec task-clock:u              #    0,993 CPUs utilized            ( +-  0,83% )
                 0      context-switches:u        #    0,000 K/sec                  
                 0      cpu-migrations:u          #    0,000 K/sec                  
             2 981      page-faults:u             #    0,013 M/sec                    ( +-  0,11% )
       337 848 080      cycles:u                  #    1,478 GHz                      ( +-  0,40% )  (60,34%)
       438 910 527      instructions:u            #    1,30  insn per cycle           ( +-  0,22% )  (73,59%)
        90 813 645      branches:u                #  397,327 M/sec                    ( +-  0,18% )  (73,62%)
         2 918 506      branch-misses:u           #    3,21% of all branches          ( +-  0,18% )  (73,74%)
       133 304 455      L1-dcache-loads:u         #  583,232 M/sec                    ( +-  0,37% )  (74,73%)
         6 939 200      L1-dcache-load-misses:u   #    5,21% of all L1-dcache hits    ( +-  0,34% )  (77,41%)
         2 235 461      LLC-loads:u               #    9,781 M/sec                    ( +-  0,36% )  (51,65%)
           510 868      LLC-load-misses:u         #   22,85% of all LL-cache hits     ( +-  0,91% )  (48,84%)

           0,23022 +- 0,00195 seconds time elapsed  ( +-  0,85% )

And some screenshots for importtime measures
Develop: https://imgur.com/lk4AslE
My improvements: https://imgur.com/0snmcEo

Checklist

• The code change is tested and works locally.
• Tests pass. Your PR cannot be merged unless tests pass. --
  poetry run behave
• The code passes linting via
  black (consistent code styling). --
  poetry run black --check . --verbose --diff
• The code passes linting via pyflakes
  (logically errors and unused imports). -- poetry run pyflakes jrnl features
• There is no commented out code in this PR.
• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open
  Pull Requests for the same update/change?
• Have you added an explanation of what your changes do and why you'd like
  us to include them?
• Have you written new tests for your core changes, as applicable?

[wren]

This looks great. Just a few small changes, and we should be good to go. Thank you!

[wren]

I agree that this is good to break out into a separate function, but without also updating upgrade_jrnl_if_necessary we now perform this check twice.

[wren]

Nitpick:

if not condition:
  return False
return True

can be more succinctly written as

return condition

[wotgl]

Hi @wren ,

Thanks for your comments! I improved code in the last commit, check it, please :)

[wren]

Thank you! 🏅