* zhanghailiang (zhang.zhanghaili...@huawei.com) wrote: > On 2015/3/5 21:31, Dr. David Alan Gilbert (git) wrote: > >From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> > > Hi Dave, > > > > >Hi, > > I'm getting COLO running on a couple of our machines here > >and wanted to see what was actually going on, so I merged > >in my recent rolling-stats code: > > > >http://lists.gnu.org/archive/html/qemu-devel/2015-03/msg00648.html > > > >with the following patch, and now I get on the primary side, > >info migrate shows me: > > > >capabilities: xbzrle: off rdma-pin-all: off auto-converge: off zero-blocks: > >off colo: on > >Migration status: colo > >total time: 0 milliseconds > >colo checkpoint (ms): Min/Max: 0, 10000 Mean: -1.1415868e-13 (Weighted: > >4.3136025e-158) Count: 4020 Values: 0@1425561742237, 0@1425561742300, > >0@1425561742363, 0@1425561742426, 0@1425561742489, 0@1425561742555, > >0@1425561742618, 0@1425561742681, 0@1425561742743, 0@1425561742824 > >colo paused time (ms): Min/Max: 55, 2789 Mean: 63.9 (Weighted: 76.243584) > >Count: 4019 Values: 62@1425561742237, 62@1425561742300, 62@1425561742363, > >62@1425561742426, 61@1425561742489, 65@1425561742555, 62@1425561742618, > >62@1425561742681, 61@1425561742743, 80@1425561742824 > >colo checkpoint size: Min/Max: 18351, 2.1731606e+08 Mean: 150096.4 > >(Weighted: 127195.56) Count: 4020 Values: 211246@1425561742238, > >186622@1425561742301, 227662@1425561742364, 219454@1425561742428, > >268702@1425561742490, 96334@1425561742556, 47086@1425561742619, > >42982@1425561742682, 55294@1425561742744, 145582@1425561742825 > > > >which suggests I've got a problem with the packet comparison; but that's > >a separate issue I'll look at. > > > > There is an obvious mistake we have made in proxy, the macro > 'IPS_UNTRACKED_BIT' in colo-patch-for-kernel.patch should be 14, > so please fix it before do the follow test. Sorry for this low-grade mistake, > we should do full test before issue it. ;)
No, that's OK; we all make them. However, that didn't cure my problem; but after a bit of experimentation I now have COLO working pretty well; thanks for the help! 1) I had to disable IPv6 in the guest; it doesn't look like the conntrack is coping with IPv6 ICMPV6, and on our test network we're getting a few 10s of those each second, so it's constant miscompares (they seem to be neighbour broadcasts and multicast stuff). 2) It looks like virtio-net is sending ARPs - possibly every time that a snapshot is loaded; it's not the 'qemu' announce-self code, (I added some debug there and it's not being called); and ARPs cause a miscompare - so you get a continuous streem of miscompares because a miscompare triggers a new snapshot, that sends more ARPs. I solved this by switching to e1000. 3) The other problem with virtio is it's occasionally triggering a 'virtio: error trying to map MMIO memory' from qemu; I'm not sure why, the state COLO sends over should always be consistent. 4) With the e1000 setup; connections are generally fairly responsive, but sshing into the guest takes *ages* (10s of seconds). I'm not sure why, because a curl to a web server seems OK (less than a second) and once the ssh is open it's pretty responsive. 5) I've seen one instance of; 'qemu-system-x86_64: block/raw-posix.c:836: handle_aiocb_rw: Assertion `p - buf == aiocb->aio_nbytes' failed.' on the primary side. Stats for a mostly idle guest are now showing: colo checkpoint (ms): Min/Max: 0, 10004 Mean: 1592.1 (Weighted: 1806.214) Count: 227 Values: 1650@1425666160229, 1661@1425666161998, 1662@1425666163736, 1687@1425666165524, 811@1425666166438, 788@1425666167298, 1619@1425666168992, 1699@1425666170793, 2711@1425666173602, 1633@1425666175315 colo paused time (ms): Min/Max: 58, 2975 Mean: 90.3 (Weighted: 94.109752) Count: 227 Values: 107@1425666160337, 75@1425666162074, 100@1425666163837, 102@1425666165627, 71@1425666166510, 74@1425666167373, 101@1425666169094, 97@1425666170891, 79@1425666173682, 97@1425666175413 colo checkpoint size: Min/Max: 212252, 1.9241972e+08 Mean: 5569622.6 (Weighted: 4826386.5) Count: 227 Values: 5998892@1425666160230, 4660988@1425666161999, 6002996@1425666163737, 5945540@1425666165525, 4833356@1425666166439, 5510606@1425666167299, 5793692@1425666168993, 5584388@1425666170794, 7016684@1425666173603, 4349084@1425666175316 So, one checkpoint every ~1.5 seconds; that's just with an ssh connected and a script doing a 'curl' to it's http repeatedly. Running 'top' on the ssh with a fast refresh brings the checkpoints much faster; I guess that's because the output of top is quite random. > To be honest, the proxy part in github is not integrated, we have cut it just > for easy review and understand, so there may be some mistakes. Yes, that's OK; and I've had a few kernel crashes; normally when the qemu crashes, the kernel doesn't really like it; but that's OK, I'm sure it will get better. I added the following to make my debug easier; which is how I found the IPv6 problem. diff --git a/xt_PMYCOLO.c b/xt_PMYCOLO.c index 9e50b62..13c0b48 100644 --- a/xt_PMYCOLO.c +++ b/xt_PMYCOLO.c @@ -1072,7 +1072,7 @@ resolve_master_ct(struct sk_buff *skb, unsigned int dataoff, h = nf_conntrack_find_get(&init_net, NF_CT_DEFAULT_ZONE, &tuple); if (h == NULL) { - pr_dbg("can't find master's ct for slaver packet\n"); + pr_dbg("can't find master's ct for slaver packet (pf/l3num=%d protonum=%d)\n", l3num, protonum); return NULL; } @@ -1092,7 +1092,7 @@ nf_conntrack_slaver_in(u_int8_t pf, unsigned int hooknum, /* rcu_read_lock()ed by nf_hook_slow */ l3proto = __nf_ct_l3proto_find(pf); if (l3proto->get_l4proto(skb, skb_network_offset(skb), &dataoff, &protonum) <= 0) { - pr_dbg("slaver: l3proto not prepared to track yet or error occurred\n"); + pr_dbg("slaver: l3proto not prepared to track yet or error occurred (pf=%d)\n", pf); NF_CT_STAT_INC_ATOMIC(&init_net, error); NF_CT_STAT_INC_ATOMIC(&init_net, invalid); goto out; > > Thanks, > zhanghailiang Thanks, Dave > > > >Dave > > > >Dr. David Alan Gilbert (1): > > COLO: Add primary side rolling statistics > > > > hmp.c | 12 ++++++++++++ > > include/migration/migration.h | 3 +++ > > migration/colo.c | 15 +++++++++++++++ > > migration/migration.c | 30 ++++++++++++++++++++++++++++++ > > qapi-schema.json | 11 ++++++++++- > > 5 files changed, 70 insertions(+), 1 deletion(-) > > > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK