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Thu, 8 Jul 2021 13:19:27 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ED4E5A4064; Thu, 8 Jul 2021 13:19:26 +0000 (GMT) Received: from localhost (unknown [9.145.63.161]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Thu, 8 Jul 2021 13:19:26 +0000 (GMT) Date: Thu, 8 Jul 2021 15:19:25 +0200 From: Vasily Gorbik To: Petr Mladek Cc: Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Joe Lawrence , Heiko Carstens , Sven Schnelle , Sumanth Korikkar , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] livepatch: Speed up transition retries Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Proofpoint-GUID: lxzj2KDpD46u5wge5zXY5J3QylFjfmNy X-Proofpoint-ORIG-GUID: NCshRIEWHdJVf9H4EktqHfA6qhl1xzke X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-07-08_06:2021-07-08,2021-07-08 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 priorityscore=1501 impostorscore=0 lowpriorityscore=0 adultscore=0 mlxscore=0 suspectscore=0 phishscore=0 clxscore=1015 spamscore=0 mlxlogscore=999 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2107080073 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 08, 2021 at 12:35:24PM +0200, Petr Mladek wrote: > On Wed 2021-07-07 14:49:41, Vasily Gorbik wrote: > > That's just a racy hack for now for demonstration purposes. > > > > For s390 LPAR with 128 cpu this reduces livepatch kselftest run time > > from > > real 1m11.837s > > user 0m0.603s > > sys 0m10.940s > > > > to > > real 0m14.550s > > user 0m0.420s > > sys 0m5.779s > > > > Would smth like that be useful for production use cases? > > Any ideas how to approach that more gracefully? > > Honestly, I do not see a real life use case for this, except maybe > speeding up a test suite. > > The livepatch transition is more about reliability than about speed. > In the real life, a livepatch will be applied only once in a while. That's what I thought. Thanks for looking. Dropping this one.