Date: Fri, 26 Feb 2016 22:17:36 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-amd64@FreeBSD.org Subject: [Bug 207446] Hang bringing up vtnet(4) on >8 cpu GCE VMs Message-ID: <bug-207446-6-ZU4gYW9xGE@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-207446-6@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=207446 --- Comment #6 from Andy Carrel <wac@google.com> --- After further investigation it looks like the driver is accidentally using driver's vtnet_max_vq_pairs*2 + 1 for the control virtqueue instead of device's max_virtqueue_pairs*2 + 1. I'm about to attach a patch to current which propagates the device's max_virtqueue_pairs number in order to make sure the control virtqueue winds up in the correct place per the virtio spec. "vt_device_max_vq_pairs" The patch also exposes this as a read-only sysctl dev.vtnet.X.device_max_vq_pairs. e.g. # sysctl -a | grep vq_pair dev.vtnet.0.act_vq_pairs: 3 dev.vtnet.0.max_vq_pairs: 3 dev.vtnet.0.device_max_vq_pairs: 16 I've tested the patch successfully with a VM that supports 16 max_virtqueue_pairs with vtnet_max_vq_pairs at the default of 8, as well as hw.vtnet.mq_max_pairs=3, and with hw.vtnet.mq_disable=1. It'd be nice to include the original patch that raises VTNET_MAX_QUEUE_PAIRS as well though since that should have some performance advantages on many cpu-ed VMs. -- You are receiving this mail because: You are on the CC list for the bug.help
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