Re: problem of `tramp-handle-file-local-copy' and inline transfer compressing

[Toru TSUNEYOSHI]

Thanks for your checking.

> I've checked it, it works fine so far. But I'm curious, whether you have
> performance figures about speed improvement. IIUC, compression works only
> for files with a size greater than tramp-inline-transfer-compress-start-size
> (4096 bytes) and less than tramp-copy-size-limit (10240 bytes). I've
> copied a text file (8187 bytes) from fencepost.gnu.org to my local
> machine; the used time was 0.6 sec (w/o compression) and 0.4 sec (with
> compression), respectively.

If we use `plink' as the method, `tramp-copy-size-limit' is ineffectual,
because of '(tramp-copy-program nil) about `plink'.
For example, I copied `/plink:remotehost:/etc/termcap' (685kB) to
localhost, and the results are as follows.

  (let ((time (current-time)))
    (copy-file "/plink:remote-host:/etc/services" "~/" t)
    (format "%g secs" (time-to-seconds (time-since time))))

  ;; without compress
  => "36.983 secs"
  => "35.12 secs"

  ;; with compress
  => "6.61 secs"
  => "4.516 secs"

  ;; with pscp instead of plink
  => "19.338 secs"
  => "13.209 secs"
  => "8.152 secs"
  => "8.422 secs"
  => "5.828 secs"

To tell the truth, I set as follows.

  ("plink" ...
           (tramp-copy-program "pscp")
           ...)

and

  (setq tramp-copy-size-limit (* 1024 1024)) ; 1MB

By the above setting, I use `plink' up to 1MB. If files size is larger
than 1MB, I use `pscp'.

> 
> Maybe, you have more impressive numbers.
> 
>> --- tramp.el.original        2009-07-08 22:22:51.000000000 +0900
>> +++ tramp.el 2010-04-25 01:37:53.539160600 +0900
> 
> Btw, it would simplify the work, if you could provide patches towards
> tramp.el from the Tramp repository.
> 
> Best regards, Michael.
> 

I will do it some day. Sorry, I can't do it possibly for some
reason. Please don't expect.

Thank you, Michael.