Re: [Qemu-devel] [PATCH v3 05/10] XBZRLE: optimize XBZRLE to decrease the cache missing

[Eric Blake]

On 03/18/2014 06:24 AM, address@hidden wrote:
> From: ChenLiang <address@hidden>

In the subject: s/missing/misses/

> 
> Avoid hot pages being replaced by others to remarkably decrease cache

s/cache/cache misses/

> 
> before this patch:
> virsh qemu-monitor-command test_vm '{"execute": "query-migrate"}'
> {"return":{"expected-downtime":1020,"xbzrle-cache":{"bytes":1108284,

1.1M bytes saved by compression,

> "cache-size":8388608,"cache-miss-rate":0.987013,"pages":18297,"overflow":8,

18k pages sent compressed

> "cache-miss":1228737},"status":"active","setup-time":10,"total-time":52398,
> "ram":{"total":12466991104,"remaining":1695744,"mbps":935.559472,
> "transferred":5780760580,"dirty-sync-counter":271,"duplicate":2878530,
> "dirty-pages-rate":29130,"skipped":0,"normal-bytes":5748592640,
> "normal":1403465}},"id":"libvirt-706"}
> 
> cache-miss-rate is 98.7%, totally miss.
> 
> after optimizing:
> virsh qemu-monitor-command test_vm '{"execute": "query-migrate"}'
> {"return":{"expected-downtime":2054,"xbzrle-cache":{"bytes":5066763,

5.0M bytes saved by compression

> "cache-size":8388608,"cache-miss-rate":0.485924,"pages":194823,"overflow":0,

194k pages sent compressed

> "cache-miss":210653},"status":"active","setup-time":11,"total-time":18729,

And reduced from 52 milleseconds to just under 19 on total time.
Definite improvements!

> "ram":{"total":12466991104,"remaining":3895296,"mbps":937.663549,
> "transferred":1615042219,"dirty-sync-counter":98,"duplicate":2869840,
> "dirty-pages-rate":58781,"skipped":0,"normal-bytes":1588404224,
> "normal":387794}},"id":"libvirt-266"}
> 
> The value of cache-miss-rate decrease 49.13%.

s/decrease/decreased to/

> 
> Signed-off-by: ChenLiang <address@hidden>
> Signed-off-by: Gonglei <address@hidden>
> ---
>  arch_init.c                    |  8 +++++---
>  include/migration/page_cache.h | 10 +++++++---
>  page_cache.c                   | 23 +++++++++++++++++++----
>  3 files changed, 31 insertions(+), 10 deletions(-)
> 

Reviewed-by: Eric Blake <address@hidden>

However, I think it would be worth squashing patch 10 into this one.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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