From mboxrd@z Thu Jan 1 00:00:00 1970 From: "J. Bruce Fields" Subject: Re: [PATCH 0/3 v3] dcache: make it more scalable on large system Date: Wed, 29 May 2013 16:43:23 -0400 Message-ID: <20130529204323.GC3243@fieldses.org> References: <1369273048-60256-1-git-send-email-Waiman.Long@hp.com> <20130523094201.GA24543@dastard> <519E8B5F.3080905@hp.com> <20130527020903.GR29466@dastard> <51A624E2.3000301@hp.com> <20130529184640.GA3243@fieldses.org> <20130529203700.GM6123@two.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Waiman Long , Dave Chinner , Alexander Viro , Jeff Layton , Miklos Szeredi , Ian Kent , Sage Weil , Steve French , Trond Myklebust , Eric Paris , linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, autofs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ceph-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "Chandramouleeswaran, Aswin" , "Norton, Scott J" To: Andi Kleen Return-path: Content-Disposition: inline In-Reply-To: <20130529203700.GM6123-1g7Xle2YJi4/4alezvVtWx2eb7JE58TQ@public.gmane.org> Sender: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: On Wed, May 29, 2013 at 10:37:00PM +0200, Andi Kleen wrote: > > As Dave said before, is the last path component sufficient? Or how > > about an inode number? > > Neither works, the profiler needs to find the file and read it. > > inode searching would be incredible expensive, How fast does it need to be? Actually analyzing the profile is something you only do once after everything's over, right? > unless the file system provided a "open-by-inode" primitive Well, I suppose there is open_by_handle_at. --b. > In normal operation you only have that event when starting up the > program and when each shared library gets mapped in. > > -Andi From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967008Ab3E2Unv (ORCPT ); Wed, 29 May 2013 16:43:51 -0400 Received: from fieldses.org ([174.143.236.118]:57465 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966874Ab3E2Unr (ORCPT ); Wed, 29 May 2013 16:43:47 -0400 Date: Wed, 29 May 2013 16:43:23 -0400 From: "J. Bruce Fields" To: Andi Kleen Cc: Waiman Long , Dave Chinner , Alexander Viro , Jeff Layton , Miklos Szeredi , Ian Kent , Sage Weil , Steve French , Trond Myklebust , Eric Paris , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, autofs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, "Chandramouleeswaran, Aswin" , "Norton, Scott J" Subject: Re: [PATCH 0/3 v3] dcache: make it more scalable on large system Message-ID: <20130529204323.GC3243@fieldses.org> References: <1369273048-60256-1-git-send-email-Waiman.Long@hp.com> <20130523094201.GA24543@dastard> <519E8B5F.3080905@hp.com> <20130527020903.GR29466@dastard> <51A624E2.3000301@hp.com> <20130529184640.GA3243@fieldses.org> <20130529203700.GM6123@two.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130529203700.GM6123@two.firstfloor.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 29, 2013 at 10:37:00PM +0200, Andi Kleen wrote: > > As Dave said before, is the last path component sufficient? Or how > > about an inode number? > > Neither works, the profiler needs to find the file and read it. > > inode searching would be incredible expensive, How fast does it need to be? Actually analyzing the profile is something you only do once after everything's over, right? > unless the file system provided a "open-by-inode" primitive Well, I suppose there is open_by_handle_at. --b. > In normal operation you only have that event when starting up the > program and when each shared library gets mapped in. > > -Andi