From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8BE24C6FA86 for ; Thu, 22 Sep 2022 09:27:07 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id E7E32833CD; Thu, 22 Sep 2022 09:27:06 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.osuosl.org E7E32833CD Authentication-Results: smtp1.osuosl.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=eb2SELK6 X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 0Lbyl_s3pv2S; Thu, 22 Sep 2022 09:27:05 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp1.osuosl.org (Postfix) with ESMTPS id C58928141D; Thu, 22 Sep 2022 09:27:04 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.osuosl.org C58928141D Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 8ED8BC0033; Thu, 22 Sep 2022 09:27:04 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 42496C007E for ; Thu, 22 Sep 2022 09:27:03 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 170B581418 for ; Thu, 22 Sep 2022 09:27:03 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.osuosl.org 170B581418 X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id nvEokgZyiPQr for ; Thu, 22 Sep 2022 09:27:02 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.osuosl.org 2F849813F5 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by smtp1.osuosl.org (Postfix) with ESMTPS id 2F849813F5 for ; Thu, 22 Sep 2022 09:27:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1663838821; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=yj3DJI23V+LSbLbOkpD05qbfoHmBLlLfe1GL1sqUY0E=; b=eb2SELK6dTwXF1BUbx9GJ6YskCLGJzDXj9KWmRr8uiXW3S0bQf9rSUEHZ5Id4t6siu4cgj GUXcztmvQKGL9xr2ceif6qi4DuZck+Qt4rM+XDE4edLkh+NOAA4CBVDCIGyLeZEDP63EqR KMzeZ5VuX8KvRL08qveAcORXbGcXbIw= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-53-N-KMPRfBNFKqaE2z_2gdVQ-1; Thu, 22 Sep 2022 05:26:58 -0400 X-MC-Unique: N-KMPRfBNFKqaE2z_2gdVQ-1 Received: by mail-wm1-f70.google.com with SMTP id n7-20020a1c2707000000b003a638356355so3820803wmn.2 for ; Thu, 22 Sep 2022 02:26:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date; bh=yj3DJI23V+LSbLbOkpD05qbfoHmBLlLfe1GL1sqUY0E=; b=ArvDJFlyS7bzwgLTyeiI/WEjCFt2oGtlDy4RaAnyn9KjGl73vTDPyfEEeUMqsZoCmM JsrW2hka9T3c4YAlaNP6G5+dERg4to0nqFYGfBU+gWDtfWTmAiC5zT/hXPdn90tpKduV V1gKSLWfKkJOJN3xu2tsAETAZyt4KvrcbFjGfVaGNHxpsq2MNEgqwvKHyfbSswTtpdf4 b1vl1U463SJ3X0oPS7QdkIWEfiMEPMH5MzPYDfcrGJM2bbTARnFMlEGKkPRY8mnvNsLZ 5FR83Iqa60J0yMlEw9nhmhFfjlM1+WR201k7z1yPuKeUfxbY6aIhuxM22vo1z8K7Rm4l QRew== X-Gm-Message-State: ACrzQf2BV/vKL713ww0rkK1XQUIOQfHTVWXb0UNG1CLwSEuU2p2es2aZ XPyro2x+9pJTxup0EWFgj2PgLnTAQQXknXFFxLHXrdsVytnROIRMNqk82bsIZzjL81oU6IhamyZ Tu5HDTqQlMk/lN8sFZUUsq+/BywKSBoLzky9DR7hCww== X-Received: by 2002:a5d:64ab:0:b0:226:d997:ad5c with SMTP id m11-20020a5d64ab000000b00226d997ad5cmr1341544wrp.602.1663838816933; Thu, 22 Sep 2022 02:26:56 -0700 (PDT) X-Google-Smtp-Source: AMsMyM6w8zI1PSOatdXcP+bXy3/Br5lytITKBUKb/YxbFrzsjnCQAQ3nJh7CECAIbmV5DzXtXp2xAQ== X-Received: by 2002:a5d:64ab:0:b0:226:d997:ad5c with SMTP id m11-20020a5d64ab000000b00226d997ad5cmr1341524wrp.602.1663838816660; Thu, 22 Sep 2022 02:26:56 -0700 (PDT) Received: from redhat.com ([2.55.16.18]) by smtp.gmail.com with ESMTPSA id a1-20020a5d5701000000b00228de58ae2bsm4759663wrv.12.2022.09.22.02.26.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Sep 2022 02:26:55 -0700 (PDT) Date: Thu, 22 Sep 2022 05:26:51 -0400 From: "Michael S. Tsirkin" To: Parav Pandit Subject: Re: [PATCH v5 2/2] virtio-net: use mtu size as buffer length for big packets Message-ID: <20220922052233-mutt-send-email-mst@kernel.org> References: <20220907103420-mutt-send-email-mst@kernel.org> <20220907141447-mutt-send-email-mst@kernel.org> <20220907151026-mutt-send-email-mst@kernel.org> <20220907152156-mutt-send-email-mst@kernel.org> <20220907153425-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Cc: "virtio-dev@lists.oasis-open.org" , "sridhar.samudrala@intel.com" , "jesse.brandeburg@intel.com" , Gavi Teitz , "virtualization@lists.linux-foundation.org" , "stephen@networkplumber.org" , "loseweigh@gmail.com" , "netdev@vger.kernel.org" , "kuba@kernel.org" , "davem@davemloft.net" , Gavin Li X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Wed, Sep 07, 2022 at 07:51:38PM +0000, Parav Pandit wrote: > > > From: Michael S. Tsirkin > > Sent: Wednesday, September 7, 2022 3:36 PM > > > > On Wed, Sep 07, 2022 at 07:27:16PM +0000, Parav Pandit wrote: > > > > > > > From: Michael S. Tsirkin > > > > Sent: Wednesday, September 7, 2022 3:24 PM > > > > > > > > On Wed, Sep 07, 2022 at 07:18:06PM +0000, Parav Pandit wrote: > > > > > > > > > > > From: Michael S. Tsirkin > > > > > > Sent: Wednesday, September 7, 2022 3:12 PM > > > > > > > > > > > > Because of shallow queue of 16 entries deep. > > > > > > > > > > > > but why is the queue just 16 entries? > > > > > I explained the calculation in [1] about 16 entries. > > > > > > > > > > [1] > > > > > > > > > > > https://lore.kernel.org/netdev/PH0PR12MB54812EC7F4711C1EA4CAA119DC > > > > 419@ > > > > > PH0PR12MB5481.namprd12.prod.outlook.com/ > > > > > > > > > > > does the device not support indirect? > > > > > > > > > > > Yes, indirect feature bit is disabled on the device. > > > > > > > > OK that explains it. > > > > > > So can we proceed with v6 to contain > > > (a) updated commit message and > > > (b) function name change you suggested to drop _fields suffix? > > > > (c) replace mtu = 0 with sensibly not calling the function when mtu is > > unknown. > > > > > > > And I'd like commit log to include results of perf testing > > - with indirect feature on > Which device do you suggest using for this test? AFAIK most devices support INDIRECT, e.g. don't nvidia cards do this? > > - with mtu feature off > Why is this needed when it is not touching the area of mtu being not offered? I don't really like it that instead of checking the MTU feature bit everywhere the patch sets mtu variable to 0. Because of this it wasn't all that obvious that the patch did not affect !MTU performance (the code does change). Rereading it afresh I think it's ok. But explicit check for !MTU would be better imho making it obvious we do not need to test !MTU. -- MST _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization