Re: ZSH performance regression in 5.8.1.2-test

[Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>]

> On 27 April 2022 at 16:02 Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx> wrote:
> On Wed, Apr 27, 2022 at 7:12 AM Stephane Chazelas <stephane@xxxxxxxxxxxx> wrote:
> >
> > 2022-04-26 09:31:55 +0100, Peter Stephenson:
> > [...]
> > > Not sure how much difference it makes but to avoid additional system calls
> > > we could cache the result, invalidating it when we open a new file.
> >
> > FYI, see https://github.com/att/ast/issues/15 for the kind of
> > issue you can find with ksh93 caching read data.
> 
> I think the idea was to cache the result of the "can we lseek" test,
> not the data that was read.

Yes, I wouldn't expect that to change until we reopen the channel,
which is detectable locally within input.c as we need to set up
the pointers at the same time.

pws