From nobody Tue Jul 30 16:15:40 2024 X-Original-To: freebsd-hackers@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4WYL1w0kRJz5RV0f for ; Tue, 30 Jul 2024 16:16:04 +0000 (UTC) (envelope-from ararslan@comcast.net) Received: from resqmta-a2p-658780.sys.comcast.net (resqmta-a2p-658780.sys.comcast.net [IPv6:2001:558:fd01:2bb4::5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4WYL1t41Qbz47BL for ; Tue, 30 Jul 2024 16:16:02 +0000 (UTC) (envelope-from ararslan@comcast.net) Authentication-Results: mx1.freebsd.org; dkim=pass header.d=comcast.net header.s=20190202a header.b=2lk4nfL3; dmarc=pass (policy=quarantine) header.from=comcast.net; spf=pass (mx1.freebsd.org: domain of ararslan@comcast.net designates 2001:558:fd01:2bb4::5 as permitted sender) smtp.mailfrom=ararslan@comcast.net Received: from resomta-a2p-647652.sys.comcast.net ([96.103.145.226]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 256/256 bits) (Client did not present a certificate) by resqmta-a2p-658780.sys.comcast.net with ESMTPS id Ymsisa7rMVTmSYpVxsm3LR; Tue, 30 Jul 2024 16:15:53 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=20190202a; t=1722356153; bh=L2Ju1HV+lZZVEhAaUWoefLnU1SlQFJ/DvdK5WdU0EAc=; h=Received:Received:Content-Type:Mime-Version:Subject:From:Date: Message-Id:To:Xfinity-Spam-Result; b=2lk4nfL3sTCgYHGnTxcwQLwngoyvDdtpdFEC2IuUKYT33DtsCk6kQkk7VJPf8twD1 f4iWC64pmwoIWSI1gCphLaRVFWpWTmxQqIQ8gRABVp2Cia1lnwAOD7cdeq9dlQ6PZq txgfsYZUzaFFDLYcHs1RDrvMR/CzAJyRkqcz+EWJcgZvAscN57Xe7rzAg4ExF1ykXH 7xP8Mm4GR6yxMCAQ85A3E1sKfauvEOzRCuR/1th1/m4LpyC7YP6kUy7qiBBL35S1RI Mf1z08Qjc1bizN2PNkw9SBlWWIe5QdpVLBtsehKMghmHl/ABCW3guoRSmRIDrkGRig khwyXRLnPrXnQ== Received: from smtpclient.apple ([67.160.29.205]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 256/256 bits) (Client did not present a certificate) by resomta-a2p-647652.sys.comcast.net with ESMTPSA id YpVvsEnc8pd4XYpVwsYi1L; Tue, 30 Jul 2024 16:15:53 +0000 Content-Type: text/plain; charset=utf-8 List-Id: Technical discussions relating to FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-hackers List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-hackers@FreeBSD.org Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3774.600.62\)) Subject: Re: Diagnosing virtual machine network issues From: Alex Arslan In-Reply-To: <4AB1C33B-DD93-4484-B63A-9FF8FE612B15@comcast.net> Date: Tue, 30 Jul 2024 09:15:40 -0700 Cc: freebsd-hackers@freebsd.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <4a5a177a-5356-453c-8a09-f1d63d5d2e16@sentex.net> <4AB1C33B-DD93-4484-B63A-9FF8FE612B15@comcast.net> To: mike tancsa X-Mailer: Apple Mail (2.3774.600.62) X-CMAE-Envelope: MS4xfAEh4InnfXxmteUqlLp+uVLpZA8l6gFlzwlItECO8Sr2+JDfFeLjnOBpVRW/k74w0BFkHRPnErs+gZ25RCV5UAAQrS3JNySpBCOOGMrffpRGo+GunIAb OX8DnMAnmnPsq7EJktJaArKCCaHSPIWS6tRWT62qNQRez/5rrbkPKguI4naM0pqyi/hd3c98wkfT/VFR5wtw2f+tmsYrHEidHlsYbkPo0m1yx0ChsFNxEAy5 X-Spamd-Bar: / X-Spamd-Result: default: False [-1.00 / 15.00]; HFILTER_HELO_5(3.00)[resqmta-a2p-658780.sys.comcast.net]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-1.00)[-0.999]; DMARC_POLICY_ALLOW(-0.50)[comcast.net,quarantine]; R_SPF_ALLOW(-0.20)[+ip6:2001:558:fd01:2bb4::/64]; R_DKIM_ALLOW(-0.20)[comcast.net:s=20190202a]; MIME_GOOD(-0.10)[text/plain]; RCPT_COUNT_TWO(0.00)[2]; MIME_TRACE(0.00)[0:+]; DWL_DNSWL_NONE(0.00)[comcast.net:dkim]; ARC_NA(0.00)[]; FREEMAIL_FROM(0.00)[comcast.net]; TO_DN_SOME(0.00)[]; RCVD_TLS_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; FREEMAIL_ENVFROM(0.00)[comcast.net]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; DKIM_TRACE(0.00)[comcast.net:+]; MLMMJ_DEST(0.00)[freebsd-hackers@freebsd.org]; APPLE_MAILER_COMMON(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; ASN(0.00)[asn:7922, ipnet:2001:558::/29, country:US]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[96.103.145.226:received] X-Rspamd-Queue-Id: 4WYL1t41Qbz47BL Some progress on this front... > On Jul 19, 2024, at 9:08=E2=80=AFAM, Alex Arslan = wrote: >=20 >> If it happens frequently and you think it might be the network, = perhaps try with the Intel em driver instead of the virtio network = driver ? I forgot to mention, we swapped the virtio network device to the Intel e1000 device but haven't observed any difference. I did manage to narrow down the issue to a more minimal reproducer, = which is just a simple request to the invalid domain using libcurl, but with a 30-second timeout. (The Julia code sets that timeout internally.) I = tried compiling the reproducer and running the executable wrapped with `time` separately in the FreeBSD VM and on the Linux host. In the VM, it = actually sits and waits out the 30 seconds then errors with a timeout, and `time` reports a real time of 30.289 seconds. On the host, it's instantaneous; the resolution failure is reported immediately. I then tried setting the timeout in the VM to 31 seconds, and it produces the expected resolution failure with a real time of 30.420 seconds. I don't understand what's going on here...