From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:36442 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751857AbcHBTAD (ORCPT ); Tue, 2 Aug 2016 15:00:03 -0400 Date: Tue, 2 Aug 2016 14:48:46 -0400 From: Brian Foster To: "Darrick J. Wong" Cc: david@fromorbit.com, linux-fsdevel@vger.kernel.org, vishal.l.verma@intel.com, xfs@oss.sgi.com Subject: Re: [PATCH 20/47] xfs: increase XFS_BTREE_MAXLEVELS to fit the rmapbt Message-ID: <20160802184845.GC58152@bfoster.bfoster> References: <146907695530.25461.3225785294902719773.stgit@birch.djwong.org> <146907709719.25461.3104352212846077948.stgit@birch.djwong.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <146907709719.25461.3104352212846077948.stgit@birch.djwong.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Wed, Jul 20, 2016 at 09:58:17PM -0700, Darrick J. Wong wrote: > By my calculations, a 1,073,741,824 block AG with a 1k block size > can attain a maximum height of 9. Assuming a record size of 24 > bytes, a key/ptr size of 44 bytes, and half-full btree nodes, > we'd need 53,687,092 blocks for the records and ~6 million blocks > for the keys. That requires a btree of height 9. > > Signed-off-by: Darrick J. Wong > --- I believe you.. :) but could you add a bit more detail to the commit log just to describe the calculations (e.g., how many records per leaf block, keys per node block) so 1.) I don't have to try and figure it out ;) (and probably get it wrong) and 2.) so we have a reference in the git repo going forward? Brian > fs/xfs/libxfs/xfs_btree.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > > diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h > index b8bbb21..629ef4f 100644 > --- a/fs/xfs/libxfs/xfs_btree.h > +++ b/fs/xfs/libxfs/xfs_btree.h > @@ -133,7 +133,7 @@ do { \ > } \ > } while (0) > > -#define XFS_BTREE_MAXLEVELS 8 /* max of all btrees */ > +#define XFS_BTREE_MAXLEVELS 9 /* max of all btrees */ > > struct xfs_btree_ops { > /* size of the key and record structures */ > > _______________________________________________ > xfs mailing list > xfs@oss.sgi.com > http://oss.sgi.com/mailman/listinfo/xfs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (Postfix) with ESMTP id A39CA7CA4 for ; Tue, 2 Aug 2016 13:48:49 -0500 (CDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by relay3.corp.sgi.com (Postfix) with ESMTP id 29717AC001 for ; Tue, 2 Aug 2016 11:48:49 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by cuda.sgi.com with ESMTP id e2istbrTdiyzoXny (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Tue, 02 Aug 2016 11:48:48 -0700 (PDT) Date: Tue, 2 Aug 2016 14:48:46 -0400 From: Brian Foster Subject: Re: [PATCH 20/47] xfs: increase XFS_BTREE_MAXLEVELS to fit the rmapbt Message-ID: <20160802184845.GC58152@bfoster.bfoster> References: <146907695530.25461.3225785294902719773.stgit@birch.djwong.org> <146907709719.25461.3104352212846077948.stgit@birch.djwong.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <146907709719.25461.3104352212846077948.stgit@birch.djwong.org> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: "Darrick J. Wong" Cc: linux-fsdevel@vger.kernel.org, vishal.l.verma@intel.com, xfs@oss.sgi.com On Wed, Jul 20, 2016 at 09:58:17PM -0700, Darrick J. Wong wrote: > By my calculations, a 1,073,741,824 block AG with a 1k block size > can attain a maximum height of 9. Assuming a record size of 24 > bytes, a key/ptr size of 44 bytes, and half-full btree nodes, > we'd need 53,687,092 blocks for the records and ~6 million blocks > for the keys. That requires a btree of height 9. > > Signed-off-by: Darrick J. Wong > --- I believe you.. :) but could you add a bit more detail to the commit log just to describe the calculations (e.g., how many records per leaf block, keys per node block) so 1.) I don't have to try and figure it out ;) (and probably get it wrong) and 2.) so we have a reference in the git repo going forward? Brian > fs/xfs/libxfs/xfs_btree.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > > diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h > index b8bbb21..629ef4f 100644 > --- a/fs/xfs/libxfs/xfs_btree.h > +++ b/fs/xfs/libxfs/xfs_btree.h > @@ -133,7 +133,7 @@ do { \ > } \ > } while (0) > > -#define XFS_BTREE_MAXLEVELS 8 /* max of all btrees */ > +#define XFS_BTREE_MAXLEVELS 9 /* max of all btrees */ > > struct xfs_btree_ops { > /* size of the key and record structures */ > > _______________________________________________ > xfs mailing list > xfs@oss.sgi.com > http://oss.sgi.com/mailman/listinfo/xfs _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs