[SLOF] [PATCH] base: increase catpad buffer

[Segher Boessenkool]

On Tue, Nov 28, 2017 at 03:31:43PM +0530, Nikunj A Dadhania wrote:
> Segher Boessenkool <segher at kernel.crashing.org> writes:
> > On Tue, Nov 28, 2017 at 01:08:09PM +0530, Nikunj A Dadhania wrote:
> >> Current buffer of 1K is not sufficient, and causes exception if more than 20
> >> devices are used with bootindex. Increase the buffer size to 16K
> >
> > Concatenating many strings this way is quadratic in the total length,
> > which is very painful with 1k already but ridiculously slow with 16k.
> > Use a better method?  $cat is a nice simple lazy utility word, it is
> > not good for constructing unbounded lists.
> 
> : load
> [...]
>    set-boot-args s" parse-load " $bootdev $cat strdup evaluate
> ;
> 
> Thats where we are hitting the limit. Maybe we can allocate and copy
> both these strings without using the catpad?

Do you need to at all?  parse-load wants to have the $bootdev string
as input buffer, so you can do

: load
  [...]
  set-boot-args
  save-source  -1 to source-id
  $boot-dev  dup #ib !  span !  to ib
  ['] parse-load catch  restore-source  throw  ;

This is just the core of EVALUATE, but calling PARSE-LOAD instead of
INTERPRET.

And yes, this can of course itself be factored better:

: $source ( str len -- )  -1 to source-id  dup #ib ! span ! to #ib  ;

: execute-with-source ( xt str len -- ??? )
  save-source  $source  catch  restore-source  throw  ;

: load
  [...]
  ['] parse-load $boot-dev execute-with-source  ;

\ and evaluate is just:
: evaluate ( str len -- ??? )  ['] interpret -rot execute-with-source  ;


Segher