Re: File path completions: strange speed discrepancy

[Michael Albinus]

JD Smith <jdtsmith@gmail.com> writes:

Hi,

> In the meantime I’ve searched down many rabbit holes and zeroed in on
> tramp’s file handlers.  I am using:
>
> (require 'tramp-sh)
> (defun my/test ()
>   (interactive)
>   (progn
>     (tramp-cleanup-all-connections)
>     (elp-instrument-list
>      '(file-remote-p
>        tramp-file-name-handler
>        completion-file-name-table
>        tramp-handle-substitute-in-file-name
>        substitute-in-file-name
>        completion--sifn-requote
>        file-name-completion
>        file-name-all-completions
>        completion--file-name-table
>        file-exists-p
>        completing-read
>        read-file-name-internal
>        read-file-name-default
>        tramp-handle-file-name-completion
>        tramp-sh-handle-file-name-all-completions))
>     (setq unread-command-events
>  (mapcar 'identity "///ssh:datpi:/home/pi/no\tex\t/do\tma\tce\t\n"))
>     (call-interactively #'find-file)
>     (let ((elp-recycle-buffers-p nil))
>       (elp-results)
>       (elp-reset-all))))
>
> ;; first browse to remote directory (here "pi")
> (progn
>   (with-current-buffer "pi"
>     (my/test))
>   (my/test))

Well, tramp-file-name-handler is just a scheduler function, which calls
the respective handler from the different Tramp backends. file-remote-p,
substitute-in-file-name, file-name-completion, file-name-all-completions
and file-exists-p don't need to be traced, because they call Tramp
functions immediately. OTOH, we might supervise all Tramp handle
functions.

Furthermore, I have switched to a remote machine in my LAN, because it
doesn't matter whether the machine is far away. So I have changed the
code snippet to

(progn
  (require 'tramp-sh)
  (defun my/test ()
    (interactive)
    (tramp-cleanup-all-connections)
    (elp-instrument-list
     (append
      '(completion-file-name-table
        completion--sifn-requote
        completion--file-name-table
        completing-read
        read-file-name-internal
        read-file-name-default)
      (mapcar #'intern (all-completions "tramp-handle-" obarray 'functionp))
      (mapcar #'intern (all-completions "tramp-sh-handle-" obarray 
'functionp))))
    (setq unread-command-events
          (mapcar 'identity "///ssh:detlef:/hom\talbin\tsr\temacs\t/lisp/\t\n"))
    (call-interactively #'find-file)
    (let ((elp-recycle-buffers-p nil))
      (elp-results)
      (elp-reset-all)))

  (dolist (df '("/ssh::" "/"))
    (let ((default-directory df))
      (my/test))))

> For me this implicates file-remote-p and tramp-file-name-handler,
> which again exhibit 10x differences between starting in a local or
> remote buffer.  If this is fixed in Emacs 28 that’s wonderful, but it
> may be several years before everyone has migrated.  

FTR, there won't be Emacs 27.3, Emacs 28.1 is the next version to be
released. In Emacs 28, I see similar discrepancies like in your test:

Results:

default-directory "/":

read-file-name-default                          1           5.866054427   
5.866054427
tramp-sh-handle-expand-file-name                408         5.1123634760  
0.0125303026
completing-read                                 1           0.821957783   
0.821957783
completion-file-name-table                      21          0.592267366   
0.0282032079
tramp-handle-file-name-completion               5           0.586021974   
0.1172043948
tramp-sh-handle-file-name-all-completions       5           0.434829428   
0.0869658856
tramp-handle-substitute-in-file-name            184         0.2953856810  
0.0016053569
tramp-sh-handle-insert-directory                1           0.271016624   
0.271016624
tramp-handle-access-file                        1           0.135264637   
0.135264637
tramp-handle-file-remote-p                      316         0.1301504470  
0.0004118685
tramp-sh-handle-file-exists-p                   21          0.127348874   
0.0060642320
tramp-sh-handle-file-truename                   1           0.112487043   
0.112487043
tramp-sh-handle-file-directory-p                46          0.0820547759  
0.0017837994
tramp-sh-handle-file-attributes                 3           0.073989483   
0.024663161
completion--sifn-requote                        7           0.071225156   
0.0101750222
tramp-handle-file-symlink-p                     1           0.057292995   
0.057292995
tramp-sh-handle-get-remote-gid                  2           0.036589462   
0.018294731
tramp-handle-file-name-case-insensitive-p       4           0.0251118690  
0.0062779672
read-file-name-internal                         16          0.024533941   
0.0015333713
completion--file-name-table                     16          0.024329729   
0.0015206080
tramp-sh-handle-file-readable-p                 1           0.022343529   
0.022343529
tramp-sh-handle-file-system-info                1           0.018551073   
0.018551073
tramp-sh-handle-get-remote-uid                  1           0.004895242   
0.004895242
tramp-handle-file-name-directory                16          0.000261404   
1.633775e-05
tramp-handle-directory-file-name                10          0.0002139559  
2.13956e-05
tramp-handle-file-name-nondirectory             12          0.0001787970  
1.489975e-05
tramp-handle-file-name-as-directory             9           0.000165349   
1.837...e-05

default-directory "/ssh::":

read-file-name-default                          1           0.851212462   
0.851212462
completing-read                                 1           0.849990537   
0.849990537
completion-file-name-table                      21          0.7683622459  
0.0365886783
tramp-handle-file-name-completion               5           0.7638386700  
0.1527677340
tramp-sh-handle-file-name-all-completions       5           0.6473699970  
0.1294739994
tramp-sh-handle-file-directory-p                31          0.1518540499  
0.0048985177
tramp-sh-handle-file-exists-p                   19          0.0916896359  
0.0048257703
tramp-handle-substitute-in-file-name            99          0.0487316130  
0.0004922385
tramp-sh-handle-file-attributes                 1           0.039626914   
0.039626914
tramp-handle-file-remote-p                      210         0.0295435460  
0.0001406835
completion--sifn-requote                        7           0.0225724849  
0.0032246407
tramp-sh-handle-get-remote-gid                  1           0.017265099   
0.017265099
tramp-sh-handle-expand-file-name                267         0.0166341830  
6.230...e-05
tramp-handle-file-name-case-insensitive-p       2           0.015025221   
0.0075126105
read-file-name-internal                         16          0.0112979599  
0.0007061224
completion--file-name-table                     16          0.01114909    
0.0006968181
tramp-handle-file-name-directory                10          0.000124537   
1.24537e-05
tramp-handle-file-name-nondirectory             6           7.415...e-05  
1.235...e-05
tramp-handle-directory-file-name                4           7.0483e-05    
1.762075e-05
tramp-handle-file-name-as-directory             2           2.8543e-05    
1.42715e-05

However, if I change the order of the test, ie if I apply

  (dolist (df '("/" "/ssh::"))

the result is different:

default-directory "/":

read-file-name-default                          1           2.028857143   
2.028857143
completing-read                                 1           2.027307814   
2.027307814
completion-file-name-table                      21          1.8559938259  
0.0883806583
tramp-handle-file-name-completion               5           1.8494828229  
0.3698965646
tramp-sh-handle-file-name-all-completions       5           1.6944888230  
0.3388977646
tramp-sh-handle-insert-directory                1           0.249578238   
0.249578238
tramp-handle-substitute-in-file-name            99          0.1388792329  
0.0014028205
tramp-sh-handle-file-exists-p                   19          0.0999807120  
0.0052621427
tramp-handle-file-remote-p                      215         0.0976847259  
0.0004543475
tramp-handle-access-file                        1           0.085786647   
0.085786647
tramp-sh-handle-file-truename                   1           0.063882702   
0.063882702
completion--sifn-requote                        7           0.0597124679  
0.0085303525
tramp-sh-handle-file-directory-p                31          0.058696891   
0.0018934480
tramp-sh-handle-file-attributes                 3           0.0531375599  
0.01771252
tramp-handle-file-symlink-p                     1           0.039325965   
0.039325965
tramp-sh-handle-expand-file-name                290         0.0263228309  
9.076...e-05
tramp-sh-handle-file-readable-p                 1           0.021077876   
0.021077876
read-file-name-internal                         16          0.017477787   
0.0010923616
tramp-sh-handle-get-remote-gid                  2           0.017327098   
0.008663549
completion--file-name-table                     16          0.0172834540  
0.0010802158
tramp-sh-handle-file-system-info                1           0.016847262   
0.016847262
tramp-handle-file-name-case-insensitive-p       2           0.007683494   
0.003841747
tramp-sh-handle-get-remote-uid                  1           0.005441875   
0.005441875
tramp-handle-file-name-directory                16          0.000245159   
1.532...e-05
tramp-handle-file-name-nondirectory             12          0.000174825   
1.456875e-05
tramp-handle-file-name-as-directory             8           0.0001712199  
2.140...e-05
tramp-handle-directory-file-name                9           0.0001689049  
1.876...e-05

default-directory "/ssh::":

read-file-name-default                          1           4.651150554   
4.651150554
tramp-sh-handle-expand-file-name                385         3.9462248850  
0.0102499347
completing-read                                 1           0.74229688    
0.74229688
completion-file-name-table                      21          0.560581997   
0.0266943808
tramp-handle-file-name-completion               5           0.555473934   
0.1110947868
tramp-sh-handle-file-name-all-completions       5           0.446917913   
0.0893835826
tramp-handle-substitute-in-file-name            184         0.2490209689  
0.0013533748
tramp-sh-handle-file-directory-p                46          0.1196519650  
0.0026011296
tramp-handle-file-remote-p                      311         0.0924080879  
0.0002971321
tramp-sh-handle-file-exists-p                   21          0.07839409    
0.0037330519
tramp-sh-handle-file-attributes                 1           0.053689036   
0.053689036
completion--sifn-requote                        7           0.043218526   
0.0061740751
read-file-name-internal                         16          0.0354457760  
0.0022153610
completion--file-name-table                     16          0.0352692769  
0.0022043298
tramp-sh-handle-get-remote-gid                  1           0.029920249   
0.029920249
tramp-handle-file-name-case-insensitive-p       4           0.017043275   
0.0042608187
tramp-handle-file-name-directory                10          0.0001320850  
1.320...e-05
tramp-handle-directory-file-name                5           0.000103661   
2.073...e-05
tramp-handle-file-name-nondirectory             6           6.9132e-05    
1.1522e-05
tramp-handle-file-name-as-directory             3           5.6996e-05    
1.899...e-05

Enough figures to analyze next days ... I have no idea yet what's up.

Best regards, Michael.