From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-x233.google.com (mail-it0-x233.google.com [IPv6:2607:f8b0:4001:c0b::233]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 60AA42202E4BE for ; Thu, 15 Mar 2018 23:11:31 -0700 (PDT) Received: by mail-it0-x233.google.com with SMTP id z7-v6so1053196iti.1 for ; Thu, 15 Mar 2018 23:17:55 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20180316025928.GB2254@thunk.org> References: <1520705944-6723-1-git-send-email-jix024@eng.ucsd.edu> <1520705944-6723-4-git-send-email-jix024@eng.ucsd.edu> <20180315045401.GB4860@magnolia> <20180316025928.GB2254@thunk.org> From: Andiry Xu Date: Thu, 15 Mar 2018 23:17:54 -0700 Message-ID: Subject: Re: [RFC v2 03/83] Add super.h. List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: "Theodore Y. Ts'o" , Arnd Bergmann , Andiry Xu , "Darrick J. Wong" , Linux FS Devel , Linux Kernel Mailing List , "linux-nvdimm@lists.01.org" , Dan Williams , "Rudoff, Andy" , coughlan@redhat.com, Steven Swanson , Dave Chinner , Jan Kara , swhiteho@redhat.com, miklos@szeredi.hu, Jian Xu , Andiry Xu List-ID: On Thu, Mar 15, 2018 at 7:59 PM, Theodore Y. Ts'o wrote: > On Thu, Mar 15, 2018 at 09:38:29PM +0100, Arnd Bergmann wrote: >> >> You could also have a resolution of less than a nanosecond. Note >> that today, the file time stamps generated by the kernel are in >> jiffies resolution, so at best one millisecond. However, most modern >> file systems go with the 64+32 bit timestamps because it's not all >> that expensive. > > It actually depends on the architecture and the accuracy/granularity > of the timekeeping hardware available to the system, but it's possible > for the granularity of file time stamps to be up to one nanosecond. > So you can get results like this: > > % stat unix_io.o > File: unix_io.o > Size: 55000 Blocks: 112 IO Block: 4096 regular file > Device: fc01h/64513d Inode: 19931278 Links: 1 > Access: (0644/-rw-r--r--) Uid: (15806/ tytso) Gid: (15806/ tytso) > Access: 2018-03-15 18:09:21.679914182 -0400 > Modify: 2018-03-15 18:09:21.639914089 -0400 > Change: 2018-03-15 18:09:21.639914089 -0400 > Thanks for all the suggestions. I think I will follow ext4's time format. 2446 should be far away enough. Thanks, Andiry _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751328AbeCPGR5 (ORCPT ); Fri, 16 Mar 2018 02:17:57 -0400 Received: from mail-it0-f50.google.com ([209.85.214.50]:33676 "EHLO mail-it0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750762AbeCPGRz (ORCPT ); Fri, 16 Mar 2018 02:17:55 -0400 X-Google-Smtp-Source: AG47ELuwpypon59loEkGnkBwwq+OINfSZQ5ZXKTMNwLqFJ0Ohtr0ZBXxQOxwJHh7FMjzmyiJRPnTkR6X0JJ/qOkopSI= MIME-Version: 1.0 In-Reply-To: <20180316025928.GB2254@thunk.org> References: <1520705944-6723-1-git-send-email-jix024@eng.ucsd.edu> <1520705944-6723-4-git-send-email-jix024@eng.ucsd.edu> <20180315045401.GB4860@magnolia> <20180316025928.GB2254@thunk.org> From: Andiry Xu Date: Thu, 15 Mar 2018 23:17:54 -0700 Message-ID: Subject: Re: [RFC v2 03/83] Add super.h. To: "Theodore Y. Ts'o" , Arnd Bergmann , Andiry Xu , "Darrick J. Wong" , Linux FS Devel , Linux Kernel Mailing List , "linux-nvdimm@lists.01.org" , Dan Williams , "Rudoff, Andy" , coughlan@redhat.com, Steven Swanson , Dave Chinner , Jan Kara , swhiteho@redhat.com, miklos@szeredi.hu, Jian Xu , Andiry Xu Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 15, 2018 at 7:59 PM, Theodore Y. Ts'o wrote: > On Thu, Mar 15, 2018 at 09:38:29PM +0100, Arnd Bergmann wrote: >> >> You could also have a resolution of less than a nanosecond. Note >> that today, the file time stamps generated by the kernel are in >> jiffies resolution, so at best one millisecond. However, most modern >> file systems go with the 64+32 bit timestamps because it's not all >> that expensive. > > It actually depends on the architecture and the accuracy/granularity > of the timekeeping hardware available to the system, but it's possible > for the granularity of file time stamps to be up to one nanosecond. > So you can get results like this: > > % stat unix_io.o > File: unix_io.o > Size: 55000 Blocks: 112 IO Block: 4096 regular file > Device: fc01h/64513d Inode: 19931278 Links: 1 > Access: (0644/-rw-r--r--) Uid: (15806/ tytso) Gid: (15806/ tytso) > Access: 2018-03-15 18:09:21.679914182 -0400 > Modify: 2018-03-15 18:09:21.639914089 -0400 > Change: 2018-03-15 18:09:21.639914089 -0400 > Thanks for all the suggestions. I think I will follow ext4's time format. 2446 should be far away enough. Thanks, Andiry