From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36141) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1elK5y-0008IS-1Q for qemu-devel@nongnu.org; Mon, 12 Feb 2018 14:48:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1elK5t-0007tN-Ou for qemu-devel@nongnu.org; Mon, 12 Feb 2018 14:48:58 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:39018 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1elK5t-0007rx-IN for qemu-devel@nongnu.org; Mon, 12 Feb 2018 14:48:53 -0500 References: <20180211093607.27351-1-armbru@redhat.com> <20180211093607.27351-11-armbru@redhat.com> From: Eric Blake Message-ID: Date: Mon, 12 Feb 2018 13:48:36 -0600 MIME-Version: 1.0 In-Reply-To: <20180211093607.27351-11-armbru@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 10/29] qapi: Touch generated files only when they change List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster , qemu-devel@nongnu.org Cc: mdroth@linux.vnet.ibm.com, marcandre.lureau@redhat.com On 02/11/2018 03:35 AM, Markus Armbruster wrote: > A massive number of objects depends on QAPI-generated headers. In my > "build everything" tree, it's roughly 4800 out of 5100. This is > particularly annoying when only some of the generated files change, > say for a doc fix. > > Improve qapi-gen.py to touch its output files only if they actually > change. Rebuild time for a QAPI doc fix drops from many minutes to a > few seconds. Rebuilds get faster for certain code changes, too. For > instance, adding a simple QMP event now recompiles less than 200 > instead of 4800 objects. But adding a QAPI type is as bad as ever; > we've clearly got more work to do. > > Signed-off-by: Markus Armbruster > Reviewed-by: Eric Blake > --- > scripts/qapi/common.py | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py > index 8290795dc1..2e58573a39 100644 > --- a/scripts/qapi/common.py > +++ b/scripts/qapi/common.py > @@ -1951,9 +1951,16 @@ class QAPIGen(object): > except os.error as e: > if e.errno != errno.EEXIST: > raise > - f = open(os.path.join(output_dir, fname), 'w') > - f.write(self._top(fname) + self._preamble + self._body > + fd = os.open(os.path.join(output_dir, fname), > + os.O_RDWR | os.O_CREAT, 0666) patchew complained here for mingw; I'm not sure why. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org