From owner-freebsd-virtualization@freebsd.org Tue Jul 24 21:30:38 2018 Return-Path: Delivered-To: freebsd-virtualization@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C424C1056A38 for ; Tue, 24 Jul 2018 21:30:38 +0000 (UTC) (envelope-from asomers@gmail.com) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 5EF6680F5A for ; Tue, 24 Jul 2018 21:30:38 +0000 (UTC) (envelope-from asomers@gmail.com) Received: by mailman.ysv.freebsd.org (Postfix) id 23EFC1056A37; Tue, 24 Jul 2018 21:30:38 +0000 (UTC) Delivered-To: virtualization@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 01FEB1056A36 for ; Tue, 24 Jul 2018 21:30:38 +0000 (UTC) (envelope-from asomers@gmail.com) Received: from mail-lf1-x132.google.com (mail-lf1-x132.google.com [IPv6:2a00:1450:4864:20::132]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 6EC5B80F51 for ; Tue, 24 Jul 2018 21:30:34 +0000 (UTC) (envelope-from asomers@gmail.com) Received: by mail-lf1-x132.google.com with SMTP id v22-v6so3976612lfe.8 for ; Tue, 24 Jul 2018 14:30:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:sender:from:date:message-id:subject:to; bh=WIO6KopsNF7Zk71CvsXyZBdZoR6cECvzFXXfs1a4H1E=; b=AMxZdRwql6gvrV0rOpufDdVjzQhqTvfFz0DeqEitx+f1Mhu6GVy8zVT5Xu2Rw5E22a 5E7+HRpsYul2LgT5Y+Omp653DfKfZWxgatOySYfGiGM8mbUWPDUk/5/xd7fFQAH271sU EZodqQD3X1hbar9rubfUZvhJi8az+3+YJtENRDDY4/SgojDq0FdFPiwQfL8f0jBY5lW2 sXg3rPGurqmP2lrqF5/XI9PgdDv4T8UW0+Ke5EFU4WLUTo2p3Ff06jIwsExJuD+SHwjx MQit/fdZhlblMQYBZYglBRsNJAYw4U1Rqxrb8wIbmkBoM+bSBO4wkvG2LmfHs0dyBasp oHyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:from:date:message-id:subject :to; bh=WIO6KopsNF7Zk71CvsXyZBdZoR6cECvzFXXfs1a4H1E=; b=KRy5JwkYen5JQpkJx6LtK9aiVnzAIgr95Rv8T2noZtHLExrU5CIJpbxohQ0UQUU8WR 7PQlwXmrW+H6bZH7obsQy9gfnT3FrTyAeXKJNYj9b1Ba5/kKOw/JUHVMhlcc2WRAEpsv X+MO/JPaw9Pkx+Yglurj+uH1j+KUQ/mTcQjSMz/a9/NcYGlL8UIGHlJQLDIk0Fizne1Y sMByC0C5KyjNl6a6q6Nos8/fPhKYk7WSJ+p1+iZ33Cvkti2MFvVlY4TMjxrl3FguSMYa DLzOAoopenCvHTinh3RYOje2yTzYG/zcfB4yNGHKvTL9aTDIKofCrofQIo4+HZTUx8Nx ZrCw== X-Gm-Message-State: AOUpUlF1H5/qTQmtk1QNXnHgGLLQwXz+sQFM6gHEd2rgEnF8V3NmPIhF OxADBk5u/LB78N2e8nQN9Ft8E940c9fKWcI5EKQL6Q== X-Google-Smtp-Source: AAOMgpdtLcj1YdcCBM0KDznKJ+dBy91JTIz9jU1Vz8W0JHCwWe9gatleJI7nfHFWiB6BJm1I0VyoOQQDU8fpqCuy8Pk= X-Received: by 2002:a19:df43:: with SMTP id q3-v6mr10577491lfj.53.1532467832690; Tue, 24 Jul 2018 14:30:32 -0700 (PDT) MIME-Version: 1.0 Sender: asomers@gmail.com Received: by 2002:ab3:7851:0:0:0:0:0 with HTTP; Tue, 24 Jul 2018 14:30:32 -0700 (PDT) From: Alan Somers Date: Tue, 24 Jul 2018 15:30:32 -0600 X-Google-Sender-Auth: Bn3oST8hfNJHjKCT1UZWoRcPqdU Message-ID: Subject: Overcommitting CPUs with BHyve? To: "freebsd-virtualization@freebsd.org" Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.27 X-BeenThere: freebsd-virtualization@freebsd.org X-Mailman-Version: 2.1.27 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: Tue, 24 Jul 2018 21:30:39 -0000 What are people's experiences with overcommitting CPUs in BHyve? I have an 8-core machine that often runs VMs totalling up to 5 allocated CPUs without problems. But today I got greedy. I assigned 8 cores to one VM for a big build job. Obviously, some of those were shared with the host. I also assigned it 8GB of RAM (out of 16 total). Build performance fell through the floor, even though the host was idle. Eventually I killed the build and restarted it with a more modest 2 make jobs (but the VM still had 8 cores). Performance improved. But eventually the system seemed to be mostly hung, while I had a build job running on the host as well as in the VM. I killed both build jobs, which resolved the hung processes. Then I restarted the host's build alone, and my system completely hung, with top(1) indicating that many processes were in the pfault state. So my questions are: 1) Is it a known problem to overcommit CPUs with BHyve? 2) Could this be related to the pfault hang, even though the guest was idle at the time? -Alan