Re: [PATCH] Set FILE_ATTRIBUTE_TEMPORARY on files opened by mkstemp()on WinNT

[Vaclav Haisman <V dot Haisman at sh dot cvut dot cz>]

On Thu, 21 Jul 2005, Christopher Faylor wrote:

> On Fri, Jul 22, 2005 at 03:17:33AM +0200, Vaclav Haisman wrote:
> >On Thu, 21 Jul 2005, Christopher Faylor wrote:
> >>On Fri, Jul 22, 2005 at 01:32:50AM +0200, Vaclav Haisman wrote:
> >>>the attached patch sets FILE_ATTRIBUTE_TEMPORARY on files opened by
> >>>mkstemp() on WinNT class systems.  Theoretically the OS should then be
> >>>less eager to write such files onto the physical storage and use cache
> >>>instead.
> >>
> >>Thank you for the patch but unless you can demonstrate some obvious
> >>performance improvements I don't think we'll be applying it.  You've
> >>slowed down (slightly) the common case of calling open for the uncommon
> >>case of calling mk?temp.
> >
> >I am not sure what kind of slow down do you mean.  Is it the one extra
> >call?
>
> It was more than one extra call, but yes.
>
> >In that case the attached modified patch should fix it.  The call to
> >open_with_attributes() in open() gets inlined, I have checked the
> >resulting .s file.
>
> Can you demonstrate some obvious performance improvements?  Does it
> speed up configure, make bash start up faster, make the rxvt window
> faster to show up?
>
> cgf
>


I don't think that any of the extra ifs and assignments could cause any
measurable slowdown. I also do not think that there are any _obvious_ speed
ups. It is merely a hint to the cache subsystem, not a silver bullet.

VH