From: Anthony Liguori <anthony@codemonkey.ws> To: Avi Kivity <avi@redhat.com> Cc: Anjali Kulkarni <anjali@juniper.net>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org> Subject: Re: [Qemu-devel] Hitting 29 NIC limit Date: Thu, 14 Oct 2010 07:54:22 -0500 [thread overview] Message-ID: <4CB6FD7E.7010606@codemonkey.ws> (raw) In-Reply-To: <4CB6F275.2060204@redhat.com> On 10/14/2010 07:07 AM, Avi Kivity wrote: > On 10/14/2010 12:54 AM, Anthony Liguori wrote: >> On 10/13/2010 05:32 PM, Anjali Kulkarni wrote: >>> >>> Hi, >>> >>> Using the legacy way of starting up NICs, I am hitting a limitation >>> after 29 >>> NICs ie no more than 29 are detected (that's because of the 32 PCI slot >>> limit on a single bus- 3 are already taken up) >>> I had initially increased the MAX_NICS to 48, just on my tree, to >>> get to >>> more, but ofcource that wont work. >>> Is there any way to go beyond 29 NICs the legacy way? What is the >>> maximum >>> that can be supported by the qdev mothod? >> >> I got up to 104 without trying very hard using the following script: >> >> args="" >> for slot in 5 6 7 8 9 10 11 12 13 14 15 16 17; do >> for fn in 0 1 2 3 4 5 6 7; do >> args="$args -netdev user,id=eth${slot}_${fn}" >> args="$args -device >> virtio-net-pci,addr=${slot}.${fn},netdev=eth${slot}_${fn},multifunction=on,romfile=" >> >> done >> done >> >> x86_64-softmmu/qemu-system-x86_64 -hda ~/images/linux.img ${args} >> -enable-kvm >> >> The key is to make the virtio-net devices multifunction and to fill >> out all 8 functions for each slot. > > This is unlikely to work right wrt pci hotplug. Yes. Our hotplug design is based on devices.. This is wrong, it should be based on bus-level concepts (like PCI slots). > If we want to support a large number of interfaces, we need true > multiport cards. This magic here creates a multiport virtio-net card so I'm not really sure what you're suggesting. It would certainly be nice to make this all more user friendly (and make hotplug work). Regards, Anthony Liguori > What's the motivation for such a huge number of interfaces?
WARNING: multiple messages have this Message-ID (diff)
From: Anthony Liguori <anthony@codemonkey.ws> To: Avi Kivity <avi@redhat.com> Cc: Anjali Kulkarni <anjali@juniper.net>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, "kvm@vger.kernel.org" <kvm@vger.kernel.org> Subject: Re: [Qemu-devel] Hitting 29 NIC limit Date: Thu, 14 Oct 2010 07:54:22 -0500 [thread overview] Message-ID: <4CB6FD7E.7010606@codemonkey.ws> (raw) In-Reply-To: <4CB6F275.2060204@redhat.com> On 10/14/2010 07:07 AM, Avi Kivity wrote: > On 10/14/2010 12:54 AM, Anthony Liguori wrote: >> On 10/13/2010 05:32 PM, Anjali Kulkarni wrote: >>> >>> Hi, >>> >>> Using the legacy way of starting up NICs, I am hitting a limitation >>> after 29 >>> NICs ie no more than 29 are detected (that's because of the 32 PCI slot >>> limit on a single bus- 3 are already taken up) >>> I had initially increased the MAX_NICS to 48, just on my tree, to >>> get to >>> more, but ofcource that wont work. >>> Is there any way to go beyond 29 NICs the legacy way? What is the >>> maximum >>> that can be supported by the qdev mothod? >> >> I got up to 104 without trying very hard using the following script: >> >> args="" >> for slot in 5 6 7 8 9 10 11 12 13 14 15 16 17; do >> for fn in 0 1 2 3 4 5 6 7; do >> args="$args -netdev user,id=eth${slot}_${fn}" >> args="$args -device >> virtio-net-pci,addr=${slot}.${fn},netdev=eth${slot}_${fn},multifunction=on,romfile=" >> >> done >> done >> >> x86_64-softmmu/qemu-system-x86_64 -hda ~/images/linux.img ${args} >> -enable-kvm >> >> The key is to make the virtio-net devices multifunction and to fill >> out all 8 functions for each slot. > > This is unlikely to work right wrt pci hotplug. Yes. Our hotplug design is based on devices.. This is wrong, it should be based on bus-level concepts (like PCI slots). > If we want to support a large number of interfaces, we need true > multiport cards. This magic here creates a multiport virtio-net card so I'm not really sure what you're suggesting. It would certainly be nice to make this all more user friendly (and make hotplug work). Regards, Anthony Liguori > What's the motivation for such a huge number of interfaces?
next prev parent reply other threads:[~2010-10-14 12:54 UTC|newest] Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-10-05 14:48 8 NIC limit linux_kvm 2010-10-05 15:24 ` Dustin Kirkland 2010-10-05 15:24 ` [Qemu-devel] " Dustin Kirkland [not found] ` <1286294888.11462.1398488135@webmail.messagingengine.com> [not found] ` <1286295603.7731.28.camel@x200> 2010-10-06 5:46 ` 8 NIC limit - patch - places limit at 32 linux_kvm 2010-10-06 5:46 ` [Qemu-devel] " linux_kvm 2010-10-06 12:54 ` Anthony Liguori 2010-10-06 17:11 ` linux_kvm 2010-10-07 1:39 ` Chris Wright 2010-10-13 22:18 ` [Qemu-devel] Hitting 29 NIC limit (was Re: 8 NIC limit - patch - places limit at 32) Anjali Kulkarni 2010-10-13 22:32 ` Hitting 29 NIC limit Anjali Kulkarni 2010-10-13 22:32 ` [Qemu-devel] " Anjali Kulkarni 2010-10-13 22:54 ` Anthony Liguori 2010-10-13 22:54 ` Anthony Liguori 2010-10-14 12:07 ` Avi Kivity 2010-10-14 12:07 ` Avi Kivity 2010-10-14 12:10 ` Daniel P. Berrange 2010-10-14 12:10 ` Daniel P. Berrange 2010-10-14 12:57 ` Anthony Liguori 2010-10-14 12:57 ` Anthony Liguori 2010-10-18 20:07 ` H. Peter Anvin 2010-10-18 20:07 ` H. Peter Anvin 2010-10-14 21:42 ` Richard W.M. Jones 2010-10-14 21:42 ` Richard W.M. Jones 2010-10-14 21:57 ` Anthony Liguori 2010-10-14 21:57 ` Anthony Liguori 2010-10-14 22:00 ` Anjali Kulkarni 2010-10-14 22:00 ` Anjali Kulkarni 2010-10-14 22:09 ` Anthony Liguori 2010-10-14 22:09 ` Anthony Liguori 2010-10-14 22:12 ` Anjali Kulkarni 2010-10-14 22:12 ` Anjali Kulkarni 2010-10-14 22:17 ` Anthony Liguori 2010-10-14 22:17 ` Anthony Liguori 2010-11-16 17:23 ` Michael S. Tsirkin 2010-11-16 17:23 ` [Qemu-devel] " Michael S. Tsirkin 2010-11-16 19:00 ` Anthony Liguori 2010-11-16 19:00 ` [Qemu-devel] " Anthony Liguori 2010-10-14 22:08 ` [Qemu-devel] " Richard W.M. Jones 2010-10-14 22:08 ` Richard W.M. Jones 2010-10-14 12:36 ` Markus Armbruster 2010-10-14 12:36 ` Markus Armbruster 2010-10-14 12:59 ` Anthony Liguori 2010-10-14 12:59 ` Anthony Liguori 2010-10-15 9:11 ` Markus Armbruster 2010-10-15 9:11 ` [Qemu-devel] " Markus Armbruster 2010-10-15 18:49 ` Passing in additional info to guest OS and e1000 test suite? Anjali Kulkarni 2010-10-15 18:49 ` [Qemu-devel] " Anjali Kulkarni 2010-10-15 20:02 ` Anthony Liguori 2010-10-15 20:02 ` [Qemu-devel] " Anthony Liguori 2010-10-14 12:54 ` Anthony Liguori [this message] 2010-10-14 12:54 ` [Qemu-devel] Hitting 29 NIC limit Anthony Liguori 2010-10-14 13:23 ` Avi Kivity 2010-10-14 13:23 ` Avi Kivity 2010-10-14 14:11 ` Anthony Liguori 2010-10-14 14:11 ` Anthony Liguori 2010-10-14 14:53 ` Avi Kivity 2010-10-14 14:53 ` Avi Kivity 2010-10-28 20:52 ` [Qemu-devel] Hitting 29 NIC limit (+Intel VT-c) linux_kvm 2010-11-16 17:21 ` Hitting 29 NIC limit Michael S. Tsirkin 2010-11-16 17:21 ` [Qemu-devel] " Michael S. Tsirkin [not found] ` <C9081994.3517C%anjali@juniper.net> [not found] ` <20101117105843.GB10168@redhat.com> 2010-11-18 3:09 ` Isaku Yamahata 2010-11-18 5:41 ` Wei Xu 2010-11-18 6:31 ` Isaku Yamahata 2010-11-18 6:46 ` Michael S. Tsirkin 2010-11-18 7:09 ` Isaku Yamahata 2010-11-18 7:15 ` Michael S. Tsirkin 2010-11-18 7:27 ` Isaku Yamahata 2010-11-18 11:54 ` Gerd Hoffmann 2010-11-18 23:55 ` Isaku Yamahata 2010-10-05 15:57 ` 8 " Markus Armbruster 2010-10-05 16:20 ` linux_kvm 2010-10-05 16:43 ` Brian Jackson
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