From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lf1-f51.google.com (mail-lf1-f51.google.com [209.85.167.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 883E819309C for ; Mon, 17 Jun 2024 09:30:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718616644; cv=none; b=JUM59Zrrgd0qaeFu2vsBHEWL7Z+Xsitv+4r9p6SAHn4FwB54x+SyUisvph6EMQeNoP6IgfdkMj83bEWr5vVlbKL2DOf/CmvyEVbPbNy9d0wdtrWSSGzksq+RI2nFQo0iX2wvOBSr8EDYa1SvNJNPtZvCUtBaGLAeq1bnIdh8Q8M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718616644; c=relaxed/simple; bh=QLxX4Rpj7zYvuJpj/kPpfbxaCfiDItCMeqMDeGVl4V4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=f6uC5nAicLt1yYxLXs7Ya+4lP+sEoJ5foBrnpiAB7dGlVr5EZ7OgwS+JzdUUceqhs6IvZ37Ovc100O3OjhHE/Hf2CwsE1kAiztgCL4szs3UBYz7t+LhvDyogMpaFqeJK02eUPyu7iiBdujHnY0Nf+JnJ9B/u6oBP1AcKuoRhiFA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=resnulli.us; spf=none smtp.mailfrom=resnulli.us; dkim=pass (2048-bit key) header.d=resnulli-us.20230601.gappssmtp.com header.i=@resnulli-us.20230601.gappssmtp.com header.b=cLgEJ/pa; arc=none smtp.client-ip=209.85.167.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=resnulli.us Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=resnulli.us Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=resnulli-us.20230601.gappssmtp.com header.i=@resnulli-us.20230601.gappssmtp.com header.b="cLgEJ/pa" Received: by mail-lf1-f51.google.com with SMTP id 2adb3069b0e04-52cc129c78fso108899e87.2 for ; Mon, 17 Jun 2024 02:30:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=resnulli-us.20230601.gappssmtp.com; s=20230601; t=1718616640; x=1719221440; darn=lists.linux.dev; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=8QLktAGNTjUFJei+a7Yp7B+dYTOmyOgcx1VIYD5aK+o=; b=cLgEJ/pakBnQOYn+F68Ij7PODzsYsZ85T2EMkHo3N+KmDzqz1KbDXdzwcMMjrsidEd aTjRQRpkH25zsLX60cneDSx5Fupzw6lvJRzejgHTB7QPzfL7Wg6DA7dAemTS7bH5ndpR vheYtVnHkjIyA+ItEN5iZ+0tjZMb8hdlyHwS8U9L0m1KiyhoIO3CIL52yNzRIVx9uFRD KUaqJVpduzm/Uk+onZjFRNTRNPQuA6/Gm8Rzyme2IiyOGUqreQUtM7gw//KAAMi/q2ir UmPQ4bjDn+29xi2eVTpNGSIgP8jyboghffaEZfWJzM7mqqiYmykGLBlsbP2raboyhr7w nzAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1718616640; x=1719221440; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=8QLktAGNTjUFJei+a7Yp7B+dYTOmyOgcx1VIYD5aK+o=; b=IivljjyKLanyVZ4lf2S5PrNfL5NlEReuzctmIe/H0QTZ5xSkHvwuQyiBUO1GJgPm93 A0jkmhqJGfn9D2m8h7y7iyIGwGJtLrUxJzZzvmS1aIY5fIW7vo+t30TGsjdQyvECSpId 5fcwsIxxkY/apIbHAHhlyPbTfQTqq9U2BS3jCisTVEauvu0Mut8gkEe0tnLW18JCP5cw 6KD6VOY7fU+BoDVVIpxxPiWSjhhnWiPtG0oGajiAzCS/0mKFN+pYj0ZhhMDi7c5nGBiR Fu4dtVR6AyIUcHRzj5ANkjRARWzCWO4B+Tiu/eXNKjuBOLBy+/NjsD5sOons1ovbiN+C Ih8A== X-Forwarded-Encrypted: i=1; AJvYcCVTyA6jc8MVYZbpNfDGRQhOH9oyPVd5LRyrHQqmEgKzNKt6DFIiqmcGiqTIGfXr5cWKdzP/NbT1gx54HMFpCTY/ixGvzGyBiYGa0mtdR3o= X-Gm-Message-State: AOJu0YwIVh2CoqA8OZ80Bh0lknzLgfN6Bi6doopyJNO5qy9vAXM6z9Gu NCVFxAH52juaT0ayi637BMJ6C3hlJ3/mgopTY9PFJQawZT38QBehj8S1W63tESM= X-Google-Smtp-Source: AGHT+IFeQQ3VLHyWUDWMF94tKcMqEnxKjztlgo/DGQL+ULZYyDevfiUpxD8t+PLZ6eWIpx+EZWjgJQ== X-Received: by 2002:a19:385b:0:b0:52c:9846:3b8c with SMTP id 2adb3069b0e04-52ca6e6c7ffmr5359133e87.41.1718616640555; Mon, 17 Jun 2024 02:30:40 -0700 (PDT) Received: from localhost ([193.47.165.251]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-422874e71dcsm188650685e9.44.2024.06.17.02.30.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Jun 2024 02:30:39 -0700 (PDT) Date: Mon, 17 Jun 2024 11:30:36 +0200 From: Jiri Pirko To: Jason Wang Cc: "Michael S. Tsirkin" , Jason Xing , Heng Qi , davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, xuanzhuo@linux.alibaba.com, virtualization@lists.linux.dev, ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com, netdev@vger.kernel.org Subject: Re: [patch net-next] virtio_net: add support for Byte Queue Limits Message-ID: References: <20240607062231-mutt-send-email-mst@kernel.org> <20240610101346-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Mon, Jun 17, 2024 at 03:44:55AM CEST, jasowang@redhat.com wrote: >On Mon, Jun 10, 2024 at 10:19 PM Michael S. Tsirkin wrote: >> >> On Fri, Jun 07, 2024 at 01:30:34PM +0200, Jiri Pirko wrote: >> > Fri, Jun 07, 2024 at 12:23:37PM CEST, mst@redhat.com wrote: >> > >On Fri, Jun 07, 2024 at 11:57:37AM +0200, Jiri Pirko wrote: >> > >> >True. Personally, I would like to just drop orphan mode. But I'm not >> > >> >sure others are happy with this. >> > >> >> > >> How about to do it other way around. I will take a stab at sending patch >> > >> removing it. If anyone is against and has solid data to prove orphan >> > >> mode is needed, let them provide those. >> > > >> > >Break it with no warning and see if anyone complains? >> > >> > This is now what I suggested at all. >> > >> > >No, this is not how we handle userspace compatibility, normally. >> > >> > Sure. >> > >> > Again: >> > >> > I would send orphan removal patch containing: >> > 1) no module options removal. Warn if someone sets it up >> > 2) module option to disable napi is ignored >> > 3) orphan mode is removed from code >> > >> > There is no breakage. Only, hypotetically performance downgrade in some >> > hypotetical usecase nobody knows of. >> >> Performance is why people use virtio. It's as much a breakage as any >> other bug. The main difference is, with other types of breakage, they >> are typically binary and we can not tolerate them at all. A tiny, >> negligeable performance regression might be tolarable if it brings >> other benefits. I very much doubt avoiding interrupts is >> negligeable though. And making code simpler isn't a big benefit, >> users do not care. > >It's not just making code simpler. As discussed in the past, it also >fixes real bugs. > >> >> > My point was, if someone presents >> > solid data to prove orphan is needed during the patch review, let's toss >> > out the patch. >> > >> > Makes sense? >> >> It's not hypothetical - if anything, it's hypothetical that performance >> does not regress. And we just got a report from users that see a >> regression without. So, not really. > >Probably, but do we need to define a bar here? Looking at git history, >we didn't ask a full benchmark for a lot of commits that may touch Moreover, there is no "benchmark" to run anyway, is it? >performance. > >Thanks > >> >> > >> > > >> > >-- >> > >MST >> > > >> >