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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DF4A9C4363D for ; Fri, 2 Oct 2020 13:11:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A5A452074B for ; Fri, 2 Oct 2020 13:11:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387832AbgJBNL3 (ORCPT ); Fri, 2 Oct 2020 09:11:29 -0400 Received: from jabberwock.ucw.cz ([46.255.230.98]:48028 "EHLO jabberwock.ucw.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726017AbgJBNL3 (ORCPT ); Fri, 2 Oct 2020 09:11:29 -0400 Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id D54641C0B79; Fri, 2 Oct 2020 15:11:26 +0200 (CEST) Date: Fri, 2 Oct 2020 15:11:26 +0200 From: Pavel Machek To: Ulrich Windl Cc: linux-kernel@vger.kernel.org Subject: Re: FYI: PoC: Running 100000 processes in 5.3.18 (SLES15 SP2) Message-ID: <20201002131126.GA11778@duo.ucw.cz> References: <5F76FA24020000A10003BB47@gwsmtp.uni-regensburg.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="82I3+IH0IqGh5yIs" Content-Disposition: inline In-Reply-To: <5F76FA24020000A10003BB47@gwsmtp.uni-regensburg.de> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --82I3+IH0IqGh5yIs Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! >=20 > Just in case someone is interested: As a Proof-of-Concept I started 100 t= housand processes on a big machine (72 cores). It worked! > However starting those too more than 30 minutes, and top needs more than = 30 minutes to refresh ist display. Still, interactive input via SSH works n= ice, but any file-system access seems quite slow (my test processes just us= e CPU; the do no t do any I/O). > Okay, well. So you have kind of N^2 task, new processes need time and all the all processes are already eating CPU... You are getting 55 processes per second, and that's not exactly good result. > Kernel messages while the processes were created: > kernel: [65648.247688] perf: interrupt took too long (2516 > 2500), lower= ing kernel.perf_event_max_sample_rate to 79250 > kernel: [65997.263218] perf: interrupt took too long (3146 > 3145), lower= ing kernel.perf_event_max_sample_rate to 63500 > kernel: [66790.221057] perf: interrupt took too long (3938 > 3932), lower= ing kernel.perf_event_max_sample_rate to 50750 > kernel: [69884.371426] perf: interrupt took too long (4925 > 4922), lower= ing kernel.perf_event_max_sample_rate to 40500 > I'm seething these even without trying to overload the machine. Best regards, Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --82I3+IH0IqGh5yIs Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABECAB0WIQRPfPO7r0eAhk010v0w5/Bqldv68gUCX3cm/gAKCRAw5/Bqldv6 8t55AJ9jdEGeGIv5mB9b2WVmUM9hJ749VgCfc4A7a6dA3siGKNxlAUXEFN2qOO8= =PHes -----END PGP SIGNATURE----- --82I3+IH0IqGh5yIs--