From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36454) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bCwHU-0004My-NH for qemu-devel@nongnu.org; Tue, 14 Jun 2016 17:53:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bCwHO-0003sS-Sh for qemu-devel@nongnu.org; Tue, 14 Jun 2016 17:53:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43351) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bCwHO-0003sK-MJ for qemu-devel@nongnu.org; Tue, 14 Jun 2016 17:53:50 -0400 References: <1465491514-7365-1-git-send-email-berrange@redhat.com> <1465491514-7365-2-git-send-email-berrange@redhat.com> <20160614122610.GH17919@stefanha-x1.localdomain> From: Eric Blake Message-ID: <57607CEC.7080606@redhat.com> Date: Tue, 14 Jun 2016 15:53:48 -0600 MIME-Version: 1.0 In-Reply-To: <20160614122610.GH17919@stefanha-x1.localdomain> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="cMpxebc8GWS1dQAdol8GtCsV2Nh0GlbPX" Subject: Re: [Qemu-devel] [PATCH v1 01/40] trace: add build framework for merging trace-events files List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi , "Daniel P. Berrange" Cc: Peter Maydell , qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --cMpxebc8GWS1dQAdol8GtCsV2Nh0GlbPX Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 06/14/2016 06:26 AM, Stefan Hajnoczi wrote: > On Thu, Jun 09, 2016 at 05:57:55PM +0100, Daniel P. Berrange wrote: >> +$(BUILD_DIR)/trace-events-all: $(trace-events-y:%=3D$(SRC_PATH)/%) >> + $(call quiet-command,cat $^ > $@) >=20 > $^ needs to be a stable ordering across make invocations and across > machines to avoid thrashing ccache and spuriously renumbering trace > event IDs. >=20 > I guess it is stable but just in case anyone knows of a case where $^ > would change order without any changes to the actual files (e.g. > readdir(2) returning things in a different order, make parallel jobs, > etc)... As far as I can tell from 'info make', $^ is the list of prerequisites, _in prerequisite order_, minus duplicates. So the only way the order will change is if you edit Makefile, and thus it looks stable to me. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --cMpxebc8GWS1dQAdol8GtCsV2Nh0GlbPX Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJXYHzsAAoJEKeha0olJ0Nq2cIIAIzmIm9FlHM9xmX2d44m1UWf yrCrp1+aFuBDEocOXrCFFh+bb1tTkAfo0NCCXp65tr3qd7DN/3XK2E7rVYFkGykU zHXWiHXpWcLA9xP6NcmCgNo7ibmeGKwSjxKQEiM/AUY298L9UCPoXFp9gyrhEjkn U2QiF3k5I3er0qRrxk5IboxV38M5EgZwhsRPHKAYWmjavuSiD4ozZvJSmjuPcN0t Hq/sM2/GlCTxqVL6shNohKVkxwEJrg4aEk2fIy8cgM/5W+bApFIMHjr4IbnxlEWr QGDWchTxL4oITQ+P161+RZkBFJeYQA8gqHVIHE2jAaVAzhf05EGUI21EHUWLj+Y= =g06R -----END PGP SIGNATURE----- --cMpxebc8GWS1dQAdol8GtCsV2Nh0GlbPX--