From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) (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 ECFB323CB; Thu, 24 Oct 2024 09:01:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.188 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729760498; cv=none; b=jTFotaIA819Q3So53cP/aSsoVJWnTHnWAgAWf5onLhyyAiJurWvgDqroGd570zE9AlvgfxGtuoJD+smKAQL4ek5mNYK+HBFWGK6fjEeKXFGixI4+NMsTkX4Z629SiFmCbez56a9P+sqvUsB+NIwuObovhIjhiJabRbwgSq7HHFw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729760498; c=relaxed/simple; bh=86RwdYNnZhoVzz9f/soUGnWuGwDz+UOZt81K5y2tbd0=; h=Message-ID:Date:MIME-Version:CC:Subject:To:References:From: In-Reply-To:Content-Type; b=KIHFM6M4e6KRmRSI28Yvxhr1pNQl4gGNre+CqirRDYF2YKKZhG+kaCGV16+WWnhlz7hs9K7ojR1lYhTKZDjvxdP22XcJe2KPrz1/r2GAaaJ/UgMZ7SEWcCsVnI5i1CRsWJNekzr0TzTGjFiFRVXjgCKSNkjcSecVbYs+xnFhNO4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.174]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4XZ0Fq0BKVzdkS3; Thu, 24 Oct 2024 16:58:55 +0800 (CST) Received: from kwepemm000007.china.huawei.com (unknown [7.193.23.189]) by mail.maildlp.com (Postfix) with ESMTPS id C2C2A140135; Thu, 24 Oct 2024 17:01:25 +0800 (CST) Received: from [10.67.120.192] (10.67.120.192) by kwepemm000007.china.huawei.com (7.193.23.189) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Thu, 24 Oct 2024 17:01:24 +0800 Message-ID: <5a2786ab-1c7c-4641-a3f6-3c3722f2ac14@huawei.com> Date: Thu, 24 Oct 2024 17:01:23 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird CC: , , , , , , Subject: Re: [PATCH V2 net 2/9] net: hns3: add sync command to sync io-pgtable To: Paolo Abeni , , , , , References: <20241018101059.1718375-1-shaojijie@huawei.com> <20241018101059.1718375-3-shaojijie@huawei.com> <214d37cc-96c0-4d47-bea0-3985e920d88c@redhat.com> From: Jijie Shao In-Reply-To: <214d37cc-96c0-4d47-bea0-3985e920d88c@redhat.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemm000007.china.huawei.com (7.193.23.189) on 2024/10/24 16:36, Paolo Abeni wrote: > On 10/18/24 12:10, Jijie Shao wrote: >> From: Jian Shen >> >> To avoid errors in pgtable prefectch, add a sync command to sync >> io-pagtable. >> >> In the case of large traffic, the TX bounce buffer may be used up. > It's unclear to me what do you mean for large traffic. Is that large > packets instead? > > Skimming over the previous patch, it looks like the for the bugger H/W > driver will use the bounce buffer for all packets with len < 64K. As > this driver does not support big tcp, such condition means all packets. > > So its not clear to me the 'may' part - it looks like the critical path > will always happen on the bugged H/W Sorry, actually not, I mean with tools like iperf3, we can hit the speed limit. In this case, many packets are sent within a short period of time. Therefore, the TX bounce buffer may be used up. In this case, mapping/unmapping is used for packets that cannot use the TX bounce buffer. Thanks, Jijie Shao > >> At this point, we go to mapping/unmapping on TX path again. >> So we added the sync command in driver to avoid hardware issue. > I thought the goal of the previous patch was to avoid such sync-up. > > So I don't understand why it's there. > > A more verbose explanation will help. > >> Signed-off-by: Jian Shen >> Signed-off-by: Peiyang Wang >> Signed-off-by: Jijie Shao > Also we need a fixes tag. > > Thanks, > > Paolo > >