Re: Performance degradation from long lines

[Phil Sainty]

On 27/10/18 4:34 AM, Alexander Shukaev wrote:
> Modes like `so-long' are not useful at all to resolve these issues
> (because, example it does not prevent the initial activation of the
> offending major mode, but rather only disables it afterwards).

In my experience, the initial activation of the major mode is not
part of the problem.  Could you point out an example where that is
a contributing factor?

Conversely, knowing which mode was selected is not only beneficial,
but (I think) crucial, as we *need* to filter out cases where it's
100% fine for lines to be extremely long (any binary file format,
for example).  so-long.el tests the original major mode against
`so-long-target-modes' to perform that filtering.

As such I don't think bypassing `set-auto-mode' is an option.
Or at minimum you need to know what that mode was, even if it is
never called.

e.g. I tried opening a 50M bzipped tar file with your code several
minutes ago, and I'm still waiting for that instance to finish
thinking about it.


-Phil