From: Peter Xu <peterx@redhat.com>
To: Andrey Gruzdev <andrey.gruzdev@virtuozzo.com>
Cc: Juan Quintela <quintela@redhat.com>,
Markus Armbruster <armbru@redhat.com>,
qemu-devel@nongnu.org,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>, Den Lunev <den@openvz.org>
Subject: Re: [PATCH v6 0/4] migration: UFFD write-tracking migration/snapshots
Date: Wed, 16 Dec 2020 16:02:26 -0500 [thread overview]
Message-ID: <20201216210226.GB39844@xz-x1> (raw)
In-Reply-To: <2a1f164c-94ab-0d35-96c0-792524d9ef30@virtuozzo.com>
On Tue, Dec 15, 2020 at 10:53:13PM +0300, Andrey Gruzdev wrote:
> First are series of runs without scan-rate-limiting.patch.
> Windows 10:
>
> msecs : count distribution
> 0 -> 1 : 131913 |****************************************|
> 2 -> 3 : 106 | |
> 4 -> 7 : 362 | |
> 8 -> 15 : 619 | |
> 16 -> 31 : 28 | |
> 32 -> 63 : 1 | |
> 64 -> 127 : 2 | |
>
>
> msecs : count distribution
> 0 -> 1 : 199273 |****************************************|
> 2 -> 3 : 190 | |
> 4 -> 7 : 425 | |
> 8 -> 15 : 927 | |
> 16 -> 31 : 69 | |
> 32 -> 63 : 3 | |
> 64 -> 127 : 16 | |
> 128 -> 255 : 2 | |
>
> Ubuntu 20.04:
>
> msecs : count distribution
> 0 -> 1 : 104954 |****************************************|
> 2 -> 3 : 9 | |
>
> msecs : count distribution
> 0 -> 1 : 147159 |****************************************|
> 2 -> 3 : 13 | |
> 4 -> 7 : 0 | |
> 8 -> 15 : 0 | |
> 16 -> 31 : 0 | |
> 32 -> 63 : 0 | |
> 64 -> 127 : 1 | |
>
>
> Here are runs with scan-rate-limiting.patch.
> Windows 10:
>
> msecs : count distribution
> 0 -> 1 : 234492 |****************************************|
> 2 -> 3 : 66 | |
> 4 -> 7 : 219 | |
> 8 -> 15 : 109 | |
> 16 -> 31 : 0 | |
> 32 -> 63 : 0 | |
> 64 -> 127 : 1 | |
>
> msecs : count distribution
> 0 -> 1 : 183171 |****************************************|
> 2 -> 3 : 109 | |
> 4 -> 7 : 281 | |
> 8 -> 15 : 444 | |
> 16 -> 31 : 3 | |
> 32 -> 63 : 1 | |
>
> Ubuntu 20.04:
>
> msecs : count distribution
> 0 -> 1 : 92224 |****************************************|
> 2 -> 3 : 9 | |
> 4 -> 7 : 0 | |
> 8 -> 15 : 0 | |
> 16 -> 31 : 1 | |
> 32 -> 63 : 0 | |
> 64 -> 127 : 1 | |
>
> msecs : count distribution
> 0 -> 1 : 97021 |****************************************|
> 2 -> 3 : 7 | |
> 4 -> 7 : 0 | |
> 8 -> 15 : 0 | |
> 16 -> 31 : 0 | |
> 32 -> 63 : 0 | |
> 64 -> 127 : 0 | |
> 128 -> 255 : 1 | |
>
> So, initial variant of rate-limiting makes some positive effect, but not very
> noticible. Interesting is the case of Windows guest, why the difference is so large,
> compared to Linux. The reason (theoretically) might be some of virtio or QXL drivers,
> hard to say. At least Windows VM has been configured with a set of Hyper-V
> enlightments, there's nothing to improve in domain config.
>
> For Linux guests latencies are good enough without any additional efforts.
Interesting...
>
> Also, I've missed some code to deal with snapshotting of suspended guest, so I'll made
> v7 series with the fix and also try to add more effective solution to reduce millisecond-grade
> latencies.
>
> And yes, I've used bpftrace-like tool - BCC from iovisor with python frontend. Seems a bit more
> friendly then bpftrace.
Do you think it's a good idea to also include your measurement script when
posting v7? It could be a well fit for scripts/, I think.
Seems 6.0 dev window is open; hopefully Dave or Juan would have time to look at
this series soon.
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2020-12-16 21:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 10:08 [PATCH v6 0/4] migration: UFFD write-tracking migration/snapshots Andrey Gruzdev via
2020-12-09 10:08 ` [PATCH v6 1/4] migration: introduce 'background-snapshot' migration capability Andrey Gruzdev via
2020-12-10 12:52 ` Markus Armbruster
2020-12-09 10:08 ` [PATCH v6 2/4] migration: introduce UFFD-WP low-level interface helpers Andrey Gruzdev via
2020-12-09 10:08 ` [PATCH v6 3/4] migration: support UFFD write fault processing in ram_save_iterate() Andrey Gruzdev via
2020-12-09 10:08 ` [PATCH v6 4/4] migration: implementation of background snapshot thread Andrey Gruzdev via
2020-12-11 13:13 ` [PATCH v6 0/4] migration: UFFD write-tracking migration/snapshots Andrey Gruzdev
2020-12-11 15:09 ` Peter Xu
2020-12-15 19:52 ` Andrey Gruzdev
2020-12-15 19:53 ` Andrey Gruzdev
2020-12-16 21:02 ` Peter Xu [this message]
2020-12-17 7:50 ` Andrey Gruzdev
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