From: David Laight <David.Laight@ACULAB.COM>
To: 'Andi Kleen' <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Jiri Olsa <jolsa@kernel.org>,
"alexey.budankov@linux.intel.com"
<alexey.budankov@linux.intel.com>,
"adrian.hunter@intel.com" <adrian.hunter@intel.com>
Subject: RE: [PATCH 1/2] perf: Add closing sibling events' file descriptors
Date: Tue, 11 Aug 2020 21:06:23 +0000 [thread overview]
Message-ID: <457dfe5709e642bd9b462f4c36e8ed75@AcuMS.aculab.com> (raw)
In-Reply-To: <20200811180334.GH1448395@tassilo.jf.intel.com>
> 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.
Even windows lets you redefine FDSET_SIZE before including the header.
And their select() is much more like poll() - so the limit is the number
of sockets, not the highest socket number (which do happen to be small
integers).
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2020-08-11 21:06 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-08 15:16 [PATCH 0/2] perf: Allow closing siblings' file descriptors Alexander Shishkin
2020-07-08 15:16 ` [PATCH 1/2] perf: Add closing sibling events' " Alexander Shishkin
2020-08-06 8:35 ` peterz
2020-08-06 15:32 ` Andi Kleen
2020-08-10 13:57 ` Alexander Shishkin
2020-08-10 14:45 ` Andi Kleen
2020-08-10 20:36 ` Peter Zijlstra
2020-08-11 8:12 ` Alexey Budankov
2020-08-11 14:29 ` Andi Kleen
2020-08-11 14:47 ` David Laight
2020-08-11 18:03 ` Andi Kleen
2020-08-11 21:06 ` David Laight [this message]
2020-08-11 9:47 ` Alexander Shishkin
2020-08-11 14:34 ` Andi Kleen
2020-08-11 16:21 ` Alexander Shishkin
2020-08-11 18:02 ` Andi Kleen
2020-07-08 15:16 ` [PATCH 2/2] perf record: Support closing siblings' " Alexander Shishkin
2020-07-08 21:09 ` Jiri Olsa
2020-07-16 8:42 ` [perf record] d65f0cbbc6: perf-sanity-tests.Setup_struct_perf_event_attr.fail kernel test robot
2020-07-09 8:30 ` [PATCH 0/2] perf: Allow closing siblings' file descriptors Alexey Budankov
2020-08-06 6:15 ` Adrian Hunter
2020-08-06 8:37 ` peterz
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