From: Paolo Bonzini <pbonzini@redhat.com>
To: Zhi Yong Wu <zwu.kernel@gmail.com>
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org,
stefanha@linux.vnet.ibm.com, linuxram@us.ibm.com,
wuzhy@linux.vnet.ibm.com
Subject: Re: [PATCH v2 15/15] net: invoke qemu_can_send_packet only before net queue sending function
Date: Thu, 24 May 2012 14:02:26 +0200 [thread overview]
Message-ID: <4FBE2352.7090401@redhat.com> (raw)
In-Reply-To: <CAEH94Lh-KK8tZ8g4G6P__kdLygZ_KCbE7HagG7TYOVEs+cB-zg@mail.gmail.com>
Il 24/05/2012 13:58, Zhi Yong Wu ha scritto:
>> > But you will copy packets uselessly. The code before the patch simply
>> > left them on the tap file descriptor. This is better because it
>> > involves the kernel in flow control. You are introducing "bufferbloat".
> You are correct, but can_send_packet will be invoked twice for one
> packet delivery.
Doesn't matter, it's cheap.
Paolo
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com>
To: Zhi Yong Wu <zwu.kernel@gmail.com>
Cc: wuzhy@linux.vnet.ibm.com, linuxram@us.ibm.com,
qemu-devel@nongnu.org, kvm@vger.kernel.org,
stefanha@linux.vnet.ibm.com
Subject: Re: [Qemu-devel] [PATCH v2 15/15] net: invoke qemu_can_send_packet only before net queue sending function
Date: Thu, 24 May 2012 14:02:26 +0200 [thread overview]
Message-ID: <4FBE2352.7090401@redhat.com> (raw)
In-Reply-To: <CAEH94Lh-KK8tZ8g4G6P__kdLygZ_KCbE7HagG7TYOVEs+cB-zg@mail.gmail.com>
Il 24/05/2012 13:58, Zhi Yong Wu ha scritto:
>> > But you will copy packets uselessly. The code before the patch simply
>> > left them on the tap file descriptor. This is better because it
>> > involves the kernel in flow control. You are introducing "bufferbloat".
> You are correct, but can_send_packet will be invoked twice for one
> packet delivery.
Doesn't matter, it's cheap.
Paolo
next prev parent reply other threads:[~2012-05-24 12:02 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-23 15:13 [PATCH v2 00/15] net: hub-based networking zwu.kernel
2012-05-23 15:13 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:13 ` [PATCH v2 01/15] net: Add a hub net client zwu.kernel
2012-05-23 15:13 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:13 ` [PATCH v2 02/15] net: Use hubs for the vlan feature zwu.kernel
2012-05-23 15:13 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:13 ` [PATCH v2 03/15] net: Look up 'vlan' net clients using hubs zwu.kernel
2012-05-23 15:13 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:13 ` [PATCH v2 04/15] hub: Check that hubs are configured correctly zwu.kernel
2012-05-23 15:13 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:13 ` [PATCH v2 05/15] net: Drop vlan argument to qemu_new_net_client() zwu.kernel
2012-05-23 15:13 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:13 ` [PATCH v2 06/15] net: Remove vlan qdev property zwu.kernel
2012-05-23 15:13 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:13 ` [PATCH v2 07/15] net: Remove vlan code from net.c zwu.kernel
2012-05-23 15:13 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:13 ` [PATCH v2 08/15] net: Remove VLANState zwu.kernel
2012-05-23 15:13 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:13 ` [PATCH v2 09/15] net: Rename non_vlan_clients to net_clients zwu.kernel
2012-05-23 15:13 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:14 ` [PATCH v2 10/15] net: Rename VLANClientState to NetClientState zwu.kernel
2012-05-23 15:14 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:14 ` [PATCH v2 11/15] net: Rename vc local variables to nc zwu.kernel
2012-05-23 15:14 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:14 ` [PATCH v2 12/15] net: Rename qemu_del_vlan_client() to qemu_del_net_client() zwu.kernel
2012-05-23 15:14 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:14 ` [PATCH v2 13/15] net: Remove obsolete vlan info zwu.kernel
2012-05-23 15:14 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:41 ` Jan Kiszka
2012-05-23 15:41 ` [Qemu-devel] " Jan Kiszka
2012-05-24 2:42 ` Zhi Yong Wu
2012-05-24 2:42 ` [Qemu-devel] " Zhi Yong Wu
2012-05-24 12:09 ` Jan Kiszka
2012-05-24 12:09 ` [Qemu-devel] " Jan Kiszka
2012-05-24 12:27 ` Zhi Yong Wu
2012-05-24 12:27 ` [Qemu-devel] " Zhi Yong Wu
2012-05-24 13:30 ` Jan Kiszka
2012-05-24 13:30 ` [Qemu-devel] " Jan Kiszka
2012-05-24 14:12 ` Zhi Yong Wu
2012-05-24 14:12 ` [Qemu-devel] " Zhi Yong Wu
2012-05-24 14:24 ` Jan Kiszka
2012-05-24 14:24 ` [Qemu-devel] " Jan Kiszka
2012-05-24 12:34 ` Zhi Yong Wu
2012-05-24 12:34 ` [Qemu-devel] " Zhi Yong Wu
2012-05-24 13:33 ` Jan Kiszka
2012-05-24 13:33 ` [Qemu-devel] " Jan Kiszka
2012-05-24 14:14 ` Zhi Yong Wu
2012-05-24 14:14 ` [Qemu-devel] " Zhi Yong Wu
2012-05-24 14:25 ` Jan Kiszka
2012-05-24 14:25 ` [Qemu-devel] " Jan Kiszka
2012-05-24 14:27 ` Zhi Yong Wu
2012-05-24 14:27 ` [Qemu-devel] " Zhi Yong Wu
2012-05-24 14:31 ` Jan Kiszka
2012-05-24 14:31 ` [Qemu-devel] " Jan Kiszka
2012-05-24 14:38 ` Zhi Yong Wu
2012-05-24 14:38 ` [Qemu-devel] " Zhi Yong Wu
2012-05-24 14:43 ` Jan Kiszka
2012-05-24 14:43 ` [Qemu-devel] " Jan Kiszka
2012-05-24 14:51 ` Zhi Yong Wu
2012-05-24 14:51 ` [Qemu-devel] " Zhi Yong Wu
2012-05-24 15:01 ` Jan Kiszka
2012-05-24 15:01 ` [Qemu-devel] " Jan Kiszka
2012-05-24 14:59 ` Zhi Yong Wu
2012-05-24 14:59 ` [Qemu-devel] " Zhi Yong Wu
2012-05-24 12:54 ` Zhi Yong Wu
2012-05-24 12:54 ` [Qemu-devel] " Zhi Yong Wu
2012-05-23 15:14 ` [PATCH v2 14/15] net: cleanup deliver/deliver_iov func pointers zwu.kernel
2012-05-23 15:14 ` [Qemu-devel] " zwu.kernel
2012-05-23 15:14 ` [PATCH v2 15/15] net: invoke qemu_can_send_packet only before net queue sending function zwu.kernel
2012-05-23 15:14 ` [Qemu-devel] " zwu.kernel
2012-05-23 16:00 ` Paolo Bonzini
2012-05-23 16:00 ` [Qemu-devel] " Paolo Bonzini
2012-05-24 4:05 ` Zhi Yong Wu
2012-05-24 4:05 ` [Qemu-devel] " Zhi Yong Wu
2012-05-24 10:07 ` Paolo Bonzini
2012-05-24 10:07 ` [Qemu-devel] " Paolo Bonzini
2012-05-24 11:58 ` Zhi Yong Wu
2012-05-24 11:58 ` [Qemu-devel] " Zhi Yong Wu
2012-05-24 12:02 ` Paolo Bonzini [this message]
2012-05-24 12:02 ` Paolo Bonzini
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