From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 86098C433EF for ; Thu, 14 Jun 2018 13:50:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 39E2E208D8 for ; Thu, 14 Jun 2018 13:50:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 39E2E208D8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ucw.cz Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755275AbeFNNuC (ORCPT ); Thu, 14 Jun 2018 09:50:02 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:33940 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755102AbeFNNuB (ORCPT ); Thu, 14 Jun 2018 09:50:01 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id DBD91803A9; Thu, 14 Jun 2018 15:49:59 +0200 (CEST) Date: Thu, 14 Jun 2018 15:49:59 +0200 From: Pavel Machek To: Mathieu Desnoyers Cc: Florian Weimer , carlos , Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Thomas Gleixner , linux-kernel , libc-alpha Subject: Re: Restartable Sequences system call merged into Linux Message-ID: <20180614134959.GA4084@amd> References: <1084280721.10859.1528746558696.JavaMail.zimbra@efficios.com> <31fc101a-295b-067b-1a82-7e9e509fc92f@redhat.com> <305409897.10888.1528747473727.JavaMail.zimbra@efficios.com> <091061df-3482-8762-30e4-feaf3417be11@redhat.com> <417742741.11550.1528821084084.JavaMail.zimbra@efficios.com> <20180614122759.GB8798@amd> <894222691.12973.1528981314012.JavaMail.zimbra@efficios.com> <20180614132557.GA15201@amd> <956816108.13001.1528983496098.JavaMail.zimbra@efficios.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="0OAP2g/MAC+5xKAE" Content-Disposition: inline In-Reply-To: <956816108.13001.1528983496098.JavaMail.zimbra@efficios.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --0OAP2g/MAC+5xKAE Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > >> - rseq_preempt(): on preemption, the scheduler sets the TIF_NOTIFY_RES= UME thread > >> flag, so rseq_handle_notify_resume() can check whether it's in a rse= q critical > >> section when returning to user-space, > >> - rseq_signal_deliver(): on signal delivery, rseq_handle_notify_resume= () checks > >> whether it's in a rseq critical section, > >> - rseq_migrate: on migration, the scheduler sets TIF_NOTIFY_RESUME as = well, > >=20 > > Yes, this is not likely to be noticeable. > >=20 > > But the proposal wanted to add a syscall to thread creation, right? > > And I believe that may be noticeable. >=20 > Fair point! Do we have a standard benchmark that would stress this ? Web server performance benchmarks basically test clone() performance in many cases. Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --0OAP2g/MAC+5xKAE Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlsicocACgkQMOfwapXb+vIPEACgs1vuWmzWdUvcvy34IY9uH7Rv aykAniy6xAOHIGIG+3DTiZI+Z+spFshk =CzEe -----END PGP SIGNATURE----- --0OAP2g/MAC+5xKAE--