From owner-freebsd-virtualization@freebsd.org Wed Jan 13 14:55:55 2021 Return-Path: Delivered-To: freebsd-virtualization@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id C94754DF824; Wed, 13 Jan 2021 14:55:55 +0000 (UTC) (envelope-from freebsd-rwg@gndrsh.dnsmgr.net) Received: from gndrsh.dnsmgr.net (br1.CN84in.dnsmgr.net [69.59.192.140]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4DG9Vc33jFz4mNl; Wed, 13 Jan 2021 14:55:51 +0000 (UTC) (envelope-from freebsd-rwg@gndrsh.dnsmgr.net) Received: from gndrsh.dnsmgr.net (localhost [127.0.0.1]) by gndrsh.dnsmgr.net (8.13.3/8.13.3) with ESMTP id 10DEtho7041741; Wed, 13 Jan 2021 06:55:43 -0800 (PST) (envelope-from freebsd-rwg@gndrsh.dnsmgr.net) Received: (from freebsd-rwg@localhost) by gndrsh.dnsmgr.net (8.13.3/8.13.3/Submit) id 10DEthxJ041740; Wed, 13 Jan 2021 06:55:43 -0800 (PST) (envelope-from freebsd-rwg) From: "Rodney W. Grimes" Message-Id: <202101131455.10DEthxJ041740@gndrsh.dnsmgr.net> Subject: Re: [bhyve][arm64] Number of allowed vcpus In-Reply-To: To: Mihai Carabas Date: Wed, 13 Jan 2021 06:55:43 -0800 (PST) CC: Andrei Martin , freebsd-arm@freebsd.org, freebsd-virtualization@freebsd.org X-Mailer: ELM [version 2.4ME+ PL121h (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII X-Rspamd-Queue-Id: 4DG9Vc33jFz4mNl X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=none (mx1.freebsd.org: domain of freebsd-rwg@gndrsh.dnsmgr.net has no SPF policy when checking 69.59.192.140) smtp.mailfrom=freebsd-rwg@gndrsh.dnsmgr.net X-Spamd-Result: default: False [-2.10 / 15.00]; RBL_SENDERSCORE_FAIL(0.00)[69.59.192.140:server fail]; TO_DN_SOME(0.00)[]; NEURAL_HAM_SHORT(-1.00)[-1.000]; FREEMAIL_TO(0.00)[gmail.com]; FROM_EQ_ENVFROM(0.00)[]; RCVD_TLS_LAST(0.00)[]; R_DKIM_NA(0.00)[]; ASN(0.00)[asn:13868, ipnet:69.59.192.0/19, country:US]; MIME_TRACE(0.00)[0:+]; MID_RHS_MATCH_FROM(0.00)[]; ARC_NA(0.00)[]; RBL_DBL_DONT_QUERY_IPS(0.00)[69.59.192.140:from]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; NEURAL_HAM_LONG(-1.00)[-1.000]; TAGGED_RCPT(0.00)[]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[dnsmgr.net]; AUTH_NA(1.00)[]; SPAMHAUS_ZRD(0.00)[69.59.192.140:from:127.0.2.255]; TO_MATCH_ENVRCPT_SOME(0.00)[]; R_SPF_NA(0.00)[no SPF record]; RCVD_COUNT_TWO(0.00)[2]; FREEMAIL_CC(0.00)[gmail.com,freebsd.org]; MAILMAN_DEST(0.00)[freebsd-arm,freebsd-virtualization] X-BeenThere: freebsd-virtualization@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: "Discussion of various virtualization techniques FreeBSD supports." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Jan 2021 14:55:55 -0000 > Hello, > > >From my perspective bhyve should use what is stated in the device tree if > no parameter is given and throw an error when N is greater than the device > tree value. > > Mihai That seems to be one reasonable solution. I am not very informed on what the CPU over commit situation is on an ARM cpu with respect to virtualization. I would also propose as an alternative to just do what was asked by the user, which is the current amd64 implementation, OR do as asked and emmit a warning message. I would ask given what was said above: isnt this the same situation as if the sum of all VM VCPU's is more than the total cores in the system? That is a very common situation, and one we must not restrict. > On Wed, Jan 13, 2021 at 1:55 PM Andrei Martin > wrote: > > > Hello, > > > > While working on enabling multiple virtual cpus for the arm64 virtual > > machine > > I used the bhyve's "-c N" parameter to create N cpus (it gets only the > > cpus, in contrast to the amd64). If N is smaller than the number of cores > > described in the device tree it will enable only N and if it's larger it > > will enable only the number of cores from the device tree. > > > > I don't know if it is the best approach. Another way would be to enable > > all the cpus from the device tree, no more, no less. > > > > Do you have any suggestions? > > > > Andrei > > > _______________________________________________ > freebsd-virtualization@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-virtualization > To unsubscribe, send any mail to "freebsd-virtualization-unsubscribe@freebsd.org" > -- Rod Grimes rgrimes@freebsd.org