From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from delivery.antispam.mailspamprotection.com (delivery.antispam.mailspamprotection.com [185.56.87.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4488D239562 for ; Wed, 7 Jan 2026 02:29:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=185.56.87.1 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767752973; cv=pass; b=AKX6NBs9laJSZJW3mX63Mq/O+cGVnr/mmnAE3qnnmA2QpS7OJG1trc1PI0Tqgukc0VfjeUaxFeRbgc39pL5mlYdDfJyI8IgPtE9ubGrJBccOOhE8wkPqGGOXDNi00PgO+5o7Hn7TYQMly+CvAL4IgXhHQUc9tmRsgEXSigovN0w= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767752973; c=relaxed/simple; bh=QzvbJ8y7akSoxlfvziTyU2H26u+gdjsVcxPDRT0Vekc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TxM0AcR4JmmzMiTz95/EQCkwxhOCQEmkIdgdR8h3QjPEVz6tYVqU2jKlhrQOkVhmXrI6Xm13PWTMSVIabfwitoYRCO2vkZ8ht1/ctc+BXGSKQfng2SmVSwaEmzMavyVgxYxblgVRuPRMsbajq9VCmabXmavgdok7psLv4WQYiWY= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=valla.it; spf=pass smtp.mailfrom=valla.it; dkim=pass (1024-bit key) header.d=antispam.mailspamprotection.com header.i=@antispam.mailspamprotection.com header.b=zv94NXit; dkim=pass (1024-bit key) header.d=valla.it header.i=@valla.it header.b=ahoIrKkh; arc=pass smtp.client-ip=185.56.87.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=valla.it Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=valla.it Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=antispam.mailspamprotection.com header.i=@antispam.mailspamprotection.com header.b="zv94NXit"; dkim=pass (1024-bit key) header.d=valla.it header.i=@valla.it header.b="ahoIrKkh" ARC-Seal: i=1; cv=none; a=rsa-sha256; d=outgoing.instance-europe-west4-6n59.prod.antispam.mailspamprotection.com; s=arckey; t=1767752971; b=yS1pCr2LE/9hGpp4Z2j/lAFLUXAzvZ9JfzfafYCPlxOkwCAsAv/+ijlCXNsxwAbXSkurFkVDDB 2jGZjha0vg6IO94nF/7ZdaQXWt/7czEEAG8l0PBndCzr5QTpkNZrssPOdRBAP57Fth3MBFuR4G bmHhnKBXJa2SyNH4i5J1iFY6876xgJur8hwq9Bnat8H3G8+OR5XQF8KjCJJKTsl4jvk51b1aMj nkuNJcogVzYTkhAqHql5A/kcbIPLqFVeFfPiGdLmPfMy/XBC1ylpUD4cSXbEqupKySmIbjcxaP 1rubrP4LY39S6wT/4N1A7kqxiQMfZo0yH+cAOqVcF5NftA==; ARC-Authentication-Results: i=1; outgoing.instance-europe-west4-6n59.prod.antispam.mailspamprotection.com; smtp.remote-ip=35.214.173.214; iprev=pass (214.173.214.35.bc.googleusercontent.com) smtp.remote-ip=35.214.173.214; auth=pass (LOGIN) smtp.auth=esm19.siteground.biz; dkim=pass header.d=valla.it header.s=default header.a=rsa-sha256; arc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed; d=outgoing.instance-europe-west4-6n59.prod.antispam.mailspamprotection.com; s=arckey; t=1767752971; bh=QzvbJ8y7akSoxlfvziTyU2H26u+gdjsVcxPDRT0Vekc=; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To: From:Date:DKIM-Signature:DKIM-Signature; b=jhap3ID3Mgg7BzQ20DMt2QRMn/xrEDrVmytDT0WJyc4wIQWN4RYM4lW5JmJ+PQ7Rm4a2yb339l WwDSiur7ExgKz+SvYHCnvPLu0Cazk3wy5iw9hjlGpvsjOlVtpXdOMn2V0NOS557Ug8ePSaaAIl vi+3eiW0nBIKJ5+Ay3s8p1lVQxTcUTQRklueFwP/7uLS5g5XuRa7AJ19b6fNeo1P+E4GTFqIQt PqkOFPvjGCOPI46bvM0M9/2wEm+1fKkmIatCaQIMplnoLY9jCofy6Fy278pM2443NsoFPTD/Sz dLeDe5w3R5j52WgNA3jdIu0cF5VGYWBhmGMkC1Pr0J1LIg==; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=antispam.mailspamprotection.com; s=default; h=CFBL-Feedback-ID:CFBL-Address :Content-Type:MIME-Version:Message-ID:Subject:Cc:To:From:Date:Reply-To: List-Unsubscribe:Content-Transfer-Encoding; bh=Uf1wXDnZEtrch6jvGDnIRLXBqVcbuiKUoyldZJS9XMk=; b=zv94NXitnutF9pzApggX5Ngfm3 7FCQKXCg4mfiFh5aOdcU7XGXkKeskLe9PrEHYm3IbvtgH/J7iIUmnIHJOxIu4MJTGgBHun0YcBfC7 maDfYK35bTVbyO19WkD7EQX5am4nEilD/4rOba2CDQgbKXcwj65YFiUED0mECOb2Fu8g=; Received: from 214.173.214.35.bc.googleusercontent.com ([35.214.173.214] helo=esm19.siteground.biz) by instance-europe-west4-cn9l.prod.antispam.mailspamprotection.com with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.98.1) (envelope-from ) id 1vdDqP-0000000ESIS-1pWr for virtualization@lists.linux.dev; Tue, 06 Jan 2026 20:40:00 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=valla.it; s=default; h=Subject:Cc:To:From:Date:list-help:list-unsubscribe: list-subscribe:list-post:list-owner:list-archive; bh=Uf1wXDnZEtrch6jvGDnIRLXBqVcbuiKUoyldZJS9XMk=; b=ahoIrKkh5XvAojUYOjlLBHZJj9 UwKnqiO5GWH0DmIGfHnZl6KzZzoKrvt0mxu34JRXe6dsQqeEckobi6Zf7Org+dq3JRjDFBxmAxZ+8 9ZuhEFYl5boFi+ck9u6H3Ria/w1QvyyF2vQlHE5D94dXsDeQSF7O3d3f4XicSpNaj9Yo=; Received: from [95.248.141.113] (port=63004 helo=bywater) by esm19.siteground.biz with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.98.1) (envelope-from ) id 1vdDq5-00000000DxZ-2mvq; Tue, 06 Jan 2026 20:39:37 +0000 Date: Tue, 6 Jan 2026 21:39:35 +0100 From: Francesco Valla To: Oliver Hartkopp Cc: Harald Mommer , Matias Ezequiel Vara Larsen , Marc Kleine-Budde , Vincent Mailhol , Mikhail Golubev-Ciuchea , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , linux-can@vger.kernel.org, virtualization@lists.linux.dev, Wolfgang Grandegger , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Stefano Garzarella Subject: Re: [PATCH v6] can: virtio: Add virtio CAN driver Message-ID: References: <4cf222cb-e6e3-4d09-a7d8-bc64b8e148bd@hartkopp.net> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4cf222cb-e6e3-4d09-a7d8-bc64b8e148bd@hartkopp.net> X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - esm19.siteground.biz X-AntiAbuse: Original Domain - lists.linux.dev X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - valla.it X-Source: X-Source-Args: X-Source-Dir: X-SGantispam-id: bb0fe65a68a252b19295f508ad6f37d7 AntiSpam-DLS: false AntiSpam-DLSP: AntiSpam-DLSRS: AntiSpam-TS: 1.0 CFBL-Address: feedback@antispam.mailspamprotection.com; report=arf CFBL-Feedback-ID: 1vdDqP-0000000ESIS-1pWr-feedback@antispam.mailspamprotection.com Authentication-Results: outgoing.instance-europe-west4-6n59.prod.antispam.mailspamprotection.com; iprev=pass (214.173.214.35.bc.googleusercontent.com) smtp.remote-ip=35.214.173.214; auth=pass (LOGIN) smtp.auth=esm19.siteground.biz; dkim=pass header.d=valla.it header.s=default header.a=rsa-sha256; arc=none Hello Harald, Oliver, On Tue, Jan 06, 2026 at 08:43:42PM +0100, Oliver Hartkopp wrote: > > > On 06.01.26 17:50, Harald Mommer wrote: > > > With the plain 'cangen' you are not really flooding the interface, since > > > you are only sending a random CAN frame every 200ms. The only way I can > > > reproduce this behaviour in a consistent manner is running from the host: > > > > > > while true; do cansend vcan0 134#00; done > > > > > > which seems to generate the maximum amount of traffic. > > > > > > This is not of course a realistic bus load, but is leading the system > > > (at least on my setup) to a corner case somewhere. > > > > I have no idea how long the shell needs for a loop, always used cangen -g 0 to stress the setup which is most probably faster than the shell interpreter, and sometimes did this for both directions (RX and TX). > > > > Full load is a realistic setup. And even if it was not, if something stopped working or worse crashes torturing the setup this was a problem. > > > > Yes. cangen -g 0 -i creates full load - even on real CAN > interfaces. You can also generate fixed content if you want to omit the > generation of randomized content. 'cangen -?' prints a help text. > I agree with both of you - I was simply arguing that a plain 'cangen' with no parameters is not really loading the interface. For some reason, I was only able to trigger the unwanted behavior with cansend in a while loop and not with cangen -g 0, even with fixed ID and payload. However, I suspect the issue is a matter of timing and coincidences rather than load level. > Best regards, > Oliver > Regards, Francesco