* Wen Congyang (we...@cn.fujitsu.com) wrote: > On 05/29/2015 12:24 AM, Dr. David Alan Gilbert wrote: > > * zhanghailiang (zhang.zhanghaili...@huawei.com) wrote: > >> This is the 5th version of COLO, here is only COLO frame part, include: VM > >> checkpoint, > >> failover, proxy API, block replication API, not include block replication. > >> The block part has been sent by wencongyang: > >> "[Qemu-devel] [PATCH COLO-Block v5 00/15] Block replication for continuous > >> checkpoints" > >> > >> we have finished some new features and optimization on COLO (As a > >> development branch in github), > >> but for easy of review, it is better to keep it simple now, so we will not > >> add too much new > >> codes into this frame patch set before it been totally reviewed. > >> > >> You can get the latest integrated qemu colo patches from github (Include > >> Block part): > >> https://github.com/coloft/qemu/commits/colo-v1.2-basic > >> https://github.com/coloft/qemu/commits/colo-v1.2-developing (more features) > >> > >> Please NOTE the difference between these two branch. > >> colo-v1.2-basic is exactly same with this patch series, which has basic > >> features of COLO. > >> Compared with colo-v1.2-basic, colo-v1.2-developing has some optimization > >> in the > >> process of checkpoint, including: > >> 1) separate ram and device save/load process to reduce size of extra > >> memory > >> used during checkpoint > >> 2) live migrate part of dirty pages to slave during sleep time. > >> Besides, we add some statistic info in colo-v1.2-developing, which you can > >> get these stat > >> info by using command 'info migrate'. > > > > > > Hi, > > I have that running now. > > > > Some notes: > > 1) The colo-proxy is working OK until qemu quits, and then it gets an RCU > > problem; see below > > 2) I've attached some minor tweaks that were needed to build with the > > 4.1rc kernel I'm using; > > they're very minor changes and I don't think related to (1). > > 3) I've also included some minor fixups I needed to get the -developing > > world > > to build; my compiler is fussy about unused variables etc - but I > > think the code > > in ram_save_complete in your -developing patch is wrong because there > > are two > > 'pages' variables and the one in the inner loop is the only one > > changed. > > 4) I've started trying simple benchmarks and tests now: > > a) With a simple web server most requests have very little overhead, > > the comparison > > matches most of the time; I do get quite large spikes > > (0.04s->1.05s) which I guess > > corresponds to when a checkpoint happens, but I'm not sure why the > > spike is so big, > > since the downtime isn't that big. > > I reproduce it, and we are investigating it now. > > > b) I tried something with more dynamic pages - the front page of a > > simple bugzilla > > What does 'dynamic pages' mean?
dynamic is the oppposite of static; so pages that are created at runtime. Bugzilla generates most pages using cgi-bin from templates, even for simple things, although most of the output from the cgi-bin script is the same each time. > > install; it failed the comparison every time; it took me a while to > > figure out > > why, but it generates a unique token in it's javascript each time > > (for a password reset > > link), and I guess the randomness used by that doesn't match on the > > two hosts. > > Yes. > Dave > Thanks > Wen Congyang > > > It surprised me, because I didn't expect this page to have much > > randomness > > in. > > > > 4a is really nice - it shows the benefit of COLO over the simple > > checkpointing; > > checkpoints happen very rarely. > > > > The colo-proxy rcu problem I hit shows as rcu-stalls in both primary and > > secondary > > after the qemu quits; the backtrace of the qemu stack is: > > > > [<ffffffff810d8c0c>] wait_rcu_gp+0x5c/0x80 > > [<ffffffff810ddb05>] synchronize_rcu+0x45/0xd0 > > [<ffffffffa0a251e5>] colo_node_release+0x35/0x50 [nfnetlink_colo] > > [<ffffffffa0a25795>] colonl_close_event+0xe5/0x160 [nfnetlink_colo] > > [<ffffffff81090c96>] notifier_call_chain+0x66/0x90 > > [<ffffffff8109154c>] atomic_notifier_call_chain+0x6c/0x110 > > [<ffffffff815eee07>] netlink_release+0x5b7/0x7f0 > > [<ffffffff815878bf>] sock_release+0x1f/0x90 > > [<ffffffff81587942>] sock_close+0x12/0x20 > > [<ffffffff812193c3>] __fput+0xd3/0x210 > > [<ffffffff8121954e>] ____fput+0xe/0x10 > > [<ffffffff8108d9f7>] task_work_run+0xb7/0xf0 > > [<ffffffff81002d4d>] do_notify_resume+0x8d/0xa0 > > [<ffffffff81722b66>] int_signal+0x12/0x17 > > [<ffffffffffffffff>] 0xffffffffffffffff > > > > that's with both the 423a8e268acbe3e644a16c15bc79603cfe9eb084 from > > yesterday and > > older e58e5152b74945871b00a88164901c0d46e6365e tags on colo-proxy. > > I'm not sure of the right fix; perhaps it might be possible to replace the > > synchronize_rcu in colo_node_release by a call_rcu that does the kfree > > later? > > > > Thanks, > > > > Dave > > > >> > >> You can test any branch of the above, > >> about how to test COLO, Please reference to the follow link. > >> http://wiki.qemu.org/Features/COLO. > >> > >> COLO is still in early stage, > >> your comments and feedback are warmly welcomed. > >> > >> Cc: netfilter-de...@vger.kernel.org > >> > >> TODO: > >> 1. Strengthen failover > >> 2. COLO function switch on/off > >> 2. Optimize proxy part, include proxy script. > >> 1) Remove the limitation of forward network link. > >> 2) Reuse the nfqueue_entry and NF_STOLEN to enqueue skb > >> 3. The capability of continuous FT > >> > >> v5: > >> - Replace the previous communication way between proxy and qemu with > >> nfnetlink > >> - Remove the 'forward device'parameter of xt_PMYCOLO, and now we use > >> iptables command > >> to set the 'forward device' > >> - Turn DPRINTF into trace_ calls as Dave's suggestion > >> > >> v4: > >> - New block replication scheme (use image-fleecing for sencondary side) > >> - Adress some comments from Eric Blake and Dave > >> - Add commmand colo-set-checkpoint-period to set the time of periodic > >> checkpoint > >> - Add a delay (100ms) between continuous checkpoint requests to ensure VM > >> run 100ms at least since last pause. > >> v3: > >> - use proxy instead of colo agent to compare network packets > >> - add block replication > >> - Optimize failover disposal > >> - handle shutdown > >> > >> v2: > >> - use QEMUSizedBuffer/QEMUFile as COLO buffer > >> - colo support is enabled by default > >> - add nic replication support > >> - addressed comments from Eric Blake and Dr. David Alan Gilbert > >> > >> v1: > >> - implement the frame of colo > >> > >> Wen Congyang (1): > >> COLO: Add block replication into colo process > >> > >> zhanghailiang (28): > >> configure: Add parameter for configure to enable/disable COLO support > >> migration: Introduce capability 'colo' to migration > >> COLO: migrate colo related info to slave > >> migration: Integrate COLO checkpoint process into migration > >> migration: Integrate COLO checkpoint process into loadvm > >> COLO: Implement colo checkpoint protocol > >> COLO: Add a new RunState RUN_STATE_COLO > >> QEMUSizedBuffer: Introduce two help functions for qsb > >> COLO: Save VM state to slave when do checkpoint > >> COLO RAM: Load PVM's dirty page into SVM's RAM cache temporarily > >> COLO VMstate: Load VM state into qsb before restore it > >> arch_init: Start to trace dirty pages of SVM > >> COLO RAM: Flush cached RAM into SVM's memory > >> COLO failover: Introduce a new command to trigger a failover > >> COLO failover: Implement COLO master/slave failover work > >> COLO failover: Don't do failover during loading VM's state > >> COLO: Add new command parameter 'colo_nicname' 'colo_script' for net > >> COLO NIC: Init/remove colo nic devices when add/cleanup tap devices > >> COLO NIC: Implement colo nic device interface configure() > >> COLO NIC : Implement colo nic init/destroy function > >> COLO NIC: Some init work related with proxy module > >> COLO: Handle nfnetlink message from proxy module > >> COLO: Do checkpoint according to the result of packets comparation > >> COLO: Improve checkpoint efficiency by do additional periodic > >> checkpoint > >> COLO: Add colo-set-checkpoint-period command > >> COLO NIC: Implement NIC checkpoint and failover > >> COLO: Disable qdev hotplug when VM is in COLO mode > >> COLO: Implement shutdown checkpoint > >> > >> arch_init.c | 243 +++++++++- > >> configure | 36 +- > >> hmp-commands.hx | 30 ++ > >> hmp.c | 14 + > >> hmp.h | 2 + > >> include/exec/cpu-all.h | 1 + > >> include/migration/migration-colo.h | 57 +++ > >> include/migration/migration-failover.h | 22 + > >> include/migration/migration.h | 3 + > >> include/migration/qemu-file.h | 3 +- > >> include/net/colo-nic.h | 27 ++ > >> include/net/net.h | 3 + > >> include/sysemu/sysemu.h | 3 + > >> migration/Makefile.objs | 2 + > >> migration/colo-comm.c | 68 +++ > >> migration/colo-failover.c | 48 ++ > >> migration/colo.c | 836 > >> +++++++++++++++++++++++++++++++++ > >> migration/migration.c | 60 ++- > >> migration/qemu-file-buf.c | 58 +++ > >> net/Makefile.objs | 1 + > >> net/colo-nic.c | 420 +++++++++++++++++ > >> net/tap.c | 45 +- > >> qapi-schema.json | 42 +- > >> qemu-options.hx | 10 +- > >> qmp-commands.hx | 41 ++ > >> savevm.c | 2 +- > >> scripts/colo-proxy-script.sh | 88 ++++ > >> stubs/Makefile.objs | 1 + > >> stubs/migration-colo.c | 58 +++ > >> trace-events | 11 + > >> vl.c | 39 +- > >> 31 files changed, 2235 insertions(+), 39 deletions(-) > >> create mode 100644 include/migration/migration-colo.h > >> create mode 100644 include/migration/migration-failover.h > >> create mode 100644 include/net/colo-nic.h > >> create mode 100644 migration/colo-comm.c > >> create mode 100644 migration/colo-failover.c > >> create mode 100644 migration/colo.c > >> create mode 100644 net/colo-nic.c > >> create mode 100755 scripts/colo-proxy-script.sh > >> create mode 100644 stubs/migration-colo.c > >> > >> -- > >> 1.7.12.4 > >> > >> > > -- > > Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK > > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
