Re: [PATCH 1/2] perf: Add closing sibling events' file descriptors

[Andi Kleen]

On Tue, Aug 11, 2020 at 02:47:03PM +0000, David Laight wrote:
> From: Andi Kleen
> > On Mon, Aug 10, 2020 at 10:36:32PM +0200, Peter Zijlstra wrote:
> > > On Mon, Aug 10, 2020 at 07:45:18AM -0700, Andi Kleen wrote:
> > >
> > > > Unfortunately we're kind of stuck with the old NFILE=1024 default
> > > > even though it makes little sense on modern servers.
> > >
> > > Why can't that be changed? It seems to me all of userspace changes all
> > > the time; heck that system-doofus thing flushed 20+ years of sysadmin
> > > experience down the drain, just cause. Why can't we up a file limit?
> > 
> > We could try, but I believe it's hard coded in various places outside
> > the kernel.
> 
> The place it really bites is select().
> Although the kernel supports large bitmaps glibc doesn't.
> The random bit overwrites are a PITA to debug.

Good point.

I remember I asked for a simple define to increase like glibc5 had, but 
they still didn't implement that.

-Andi