From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 57997125DF for ; Wed, 30 Oct 2024 04:11:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730261490; cv=none; b=YCjCVn/x/TKT2e7yrWQKHybmn77Eh/3KWeLzpvYEVCVU/g0VG9LOwU5Qdd+v4clBkmIRgQ/j+lRZiMUXfYqocVpFu4ax7dytJMx4ju6Z8wgJaTiZSRYkBl8zF119nM4ARpPguNNRErdDoJHb26UZCtvvVhYy7KsxpryzJlbcn/Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730261490; c=relaxed/simple; bh=KfSmvBYq+xaNY7BxHc4uMlmJklrJv/l+lMd009vbhyo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pcV645Z2yTEFsvZv4UpRIh3//UMLS91ZlYxbITNbz9nn6mJZPpaT9KuoeQPzpiAt9i1jGjz0zAamfZwy5x+3KLkB0Ertfpq0eNYnxdG2zFcWVTU+07fPRHu5pRyuIcGbkZc6m0qt6SiGTDeh8vdw8+2VioA4jWx78OOwRXMGkok= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=OutDP1Ds; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="OutDP1Ds" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1730261487; 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=SLYSYXpb7RguVtdWGdRNP6OWFD7CQmS+fcD1OXN5Krw=; b=OutDP1DsWqvG3sPclXW34bHfxZxfUfRuJhw7lPx0c4/WnRoNHP5FbRDXDSdam8UBpK141u /7TP3bmidaZstQinM4p72cgVwU+K3+0lPcHBxMrXGOtpw8CZHJftrsGmdAOduFpRAixGMa ZUHn3/MgXNR2BLIDEtE3LjYWDxrbvbA= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-689-4SdumlcJPmuvcFkLWuPXqw-1; Wed, 30 Oct 2024 00:11:23 -0400 X-MC-Unique: 4SdumlcJPmuvcFkLWuPXqw-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4863D195608C; Wed, 30 Oct 2024 04:11:22 +0000 (UTC) Received: from fedora (unknown [10.72.116.45]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EF63C1956054; Wed, 30 Oct 2024 04:11:17 +0000 (UTC) Date: Wed, 30 Oct 2024 12:11:12 +0800 From: Ming Lei To: Jens Axboe Cc: Pavel Begunkov , io-uring@vger.kernel.org, linux-block@vger.kernel.org, Uday Shankar , Akilesh Kailash Subject: Re: [PATCH V8 0/8] io_uring: support sqe group and leased group kbuf Message-ID: References: <20241025122247.3709133-1-ming.lei@redhat.com> <15b9b1e0-d961-4174-96ed-5a6287e4b38b@gmail.com> <674e8c3c-1f2c-464a-ad59-da3d00104383@kernel.dk> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 On Wed, Oct 30, 2024 at 11:08:16AM +0800, Ming Lei wrote: > On Tue, Oct 29, 2024 at 08:43:39PM -0600, Jens Axboe wrote: ... > > You could avoid the OP dependency with just a flag, if you really wanted > > to. But I'm not sure it makes a lot of sense. And it's a hell of a lot > > Yes, IO_LINK won't work for submitting multiple IOs concurrently, extra > syscall makes application too complicated, and IO latency is increased. > > > simpler than the sqe group scheme, which I'm a bit worried about as it's > > a bit complicated in how deep it needs to go in the code. This one > > stands alone, so I'd strongly encourage we pursue this a bit further and > > iron out the kinks. Maybe it won't work in the end, I don't know, but it > > seems pretty promising and it's soooo much simpler. > > If buffer register and lookup are always done in ->prep(), OP dependency > may be avoided. Even all buffer register and lookup are done in ->prep(), OP dependency still can't be avoided completely, such as: 1) two local buffers for sending to two sockets 2) group 1: IORING_OP_LOCAL_KBUF1 & [send(sock1), send(sock2)] 3) group 2: IORING_OP_LOCAL_KBUF2 & [send(sock1), send(sock2)] group 1 and group 2 needs to be linked, but inside each group, the two sends may be submitted in parallel. Thanks, Ming