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From: Gabriel Paubert <paubert@iram.es>
To: Steve French <smfrench@gmail.com>
Cc: David Howells <dhowells@redhat.com>,
	Latchesar Ionkov <lucho@ionkov.net>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	"Darrick J. Wong" <djwong@kernel.org>,
	Anders Larsen <al@alarsen.net>,
	Carlos Llamas <cmllamas@google.com>,
	Sven Schnelle <svens@linux.ibm.com>,
	Mattia Dongili <malattia@linux.it>,
	Yonghong Song <yonghong.song@linux.dev>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Christoph Hellwig <hch@lst.de>,
	Mike Marshall <hubcap@omnibond.com>,
	Paulo Alcantara <pc@manguebit.com>,
	Jason Gunthorpe <jgg@ziepe.ca>, James Morris <jmorris@namei.org>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	devel@lists.orangefs.org, Shyam Prasad N <sprasad@microsoft.com>,
	Jan Harkes <jaharkes@cs.cmu.edu>,
	linux-um@lists.infradead.org, Nicholas Piggin <n>
Subject: [OT] Re: [PATCH 86/87] fs: switch timespec64 fields in inode to discrete integers
Date: Sun, 1 Oct 2023 07:01:56 +0200	[thread overview]
Message-ID: <20231001050156.GA3366643@gp-workstation.iram.es> (raw)
In-Reply-To: <CAH2r5ms14hPaz=Ex2a=Dj0Hz3XxYLRKFj_rHHekznTbNJ_wABQ@mail.gmail.com>

On Sat, Sep 30, 2023 at 09:50:41AM -0500, Steve French wrote:
> On Fri, Sep 29, 2023 at 3:06 AM David Howells via samba-technical
> <samba-technical@lists.samba.org> wrote:
> >
> >
> > Jeff Layton <jlayton@kernel.org> wrote:
> >
> > > Correct. We'd lose some fidelity in currently stored timestamps, but as
> > > Linus and Ted pointed out, anything below ~100ns granularity is
> > > effectively just noise, as that's the floor overhead for calling into
> > > the kernel. It's hard to argue that any application needs that sort of
> > > timestamp resolution, at least with contemporary hardware.
> >
> > Albeit with the danger of making Steve French very happy;-), would it make
> > sense to switch internally to Microsoft-style 64-bit timestamps with their
> > 100ns granularity?
> 
> 100ns granularity does seem to make sense and IIRC was used by various
> DCE standards in the 90s and 2000s (not just used for SMB2/SMB3 protocol and
> various Windows filesystems)

Historically it probably comes from VMS, where system time and file
timestamps were a 64 bit integer counting in 100ns units starting on MJD
2400000.5 (Nov 17th 1858).

Gabriel

> 
> 
> -- 
> Thanks,
> 
> Steve



  reply	other threads:[~2023-10-01  5:01 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-28 11:05 [PATCH 85/87] fs: rename i_atime and i_mtime fields to __i_atime and __i_mtime Jeff Layton
2023-09-28 11:05 ` [PATCH 86/87] fs: switch timespec64 fields in inode to discrete integers Jeff Layton
2023-09-28 15:48   ` Arnd Bergmann
2023-09-28 17:06     ` Jeff Layton
2023-09-28 17:19       ` Darrick J. Wong
2023-09-28 17:40         ` Jeff Layton
2023-09-28 20:21           ` Arnd Bergmann
2023-09-28 21:26           ` Theodore Ts'o
2023-09-29  0:18             ` Linus Torvalds
2023-09-29  3:50               ` Amir Goldstein
     [not found]                 ` <CAOQ4uxg5ctY9yCjLOjN1nETAcEuNb2UERnYuDv7PoErdxX=WUw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2023-09-29 16:22                   ` Linus Torvalds
2023-09-29  3:27         ` Amir Goldstein
     [not found]         ` <6a6f37d16b55a3003af3f3dbb7778a367f68cd8d.camel-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2023-09-29  6:32           ` David Howells
2023-09-30 14:50             ` Steve French
2023-10-01  5:01               ` Gabriel Paubert [this message]
2023-09-29  9:44       ` Christian Brauner
2023-09-29 10:16         ` Jeff Layton
2023-09-28 17:09   ` Jeff Layton
2023-09-28 11:05 ` [PATCH 87/87] fs: move i_blocks up a few places in struct inode Jeff Layton
2023-09-28 11:35   ` Amir Goldstein
2023-09-28 12:01     ` Jeff Layton
2023-09-28 17:41   ` Linus Torvalds
2023-09-28 18:01     ` Jeff Layton
2023-09-29  9:32     ` Christian Brauner

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