Re: [PATCH v10 00/12] *** A Method for evaluating dirty page rate ***

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Chuan Zheng (zhengchuan@huawei.com) wrote:
> v9 -> v10:
>     rename find_page_matched as find_block_matched
>     fix wrong termination condition in find_block_matched
>     add review-by for patches
> 
> v8 -> v9:
>     fix wrong index return of record_ramblock_hash_info
>     optimize variable name according to review
>     reset dirty_rate as -1
>     change returns of compare_page_hash_info to bool
> 
> v7 -> v8:
>     add atomic_read for dirtyrate status
>     add error_report if set dirtyrate state failed
>     change returns of save_ramblock_hash and record_ramblock_hash_info to bool
>     alloc ramblock dirtyinfo array at one time
>     add review-by for patches
> 
> v6 -> v7:
>     fix minior comments and coding style by review
>     add review-by for patches
> 
> v5 -> v6:
>     fix coding style according to review
>     use TARGET_PAGE_SIZE and TARGET_PAGE_BITS instead of self-defined macros
>     return start-time and calc-time by qmp command
> 
> v4 -> v5:
>     fix git apply failed due to meson-build
>     add review-by for patches in v3
> 
> v3 -> v4:
>     use crc32 to get hash result instead of md5
>     add DirtyRateStatus to denote calculation status
>     add some trace_calls to make it easier to debug
>     fix some comments accroding to review
> 
> v2 -> v3:
>     fix size_t compile warning
>     fix codestyle checked by checkpatch.pl
> 
> v1 -> v2:
>     use g_rand_new() to generate rand_buf
>     move RAMBLOCK_FOREACH_MIGRATABLE into migration/ram.h
>     add skip_sample_ramblock to filter sampled ramblock
>     fix multi-numa vm coredump when query dirtyrate
>     rename qapi interface and rename some structures and functions
>     succeed to compile by appling each patch
>     add test for migrating vm
> 
> Sometimes it is neccessary to evaluate dirty page rate before migration.
> Users could decide whether to proceed migration based on the evaluation
> in case of vm performance loss due to heavy workload.
> Unlikey simulating dirtylog sync which could do harm on runnning vm,
> we provide a sample-hash method to compare hash results for samping page.
> In this way, it would have hardly no impact on vm performance.
> 
> Evaluate the dirtypage rate both on running and migration vm.
> The VM specifications for migration are as follows:
> - VM use 4-K page;
> - the number of VCPU is 32;
> - the total memory is 32Gigabit;
> - use 'mempress' tool to pressurize VM(mempress 4096 1024);
> - migration bandwidth is 1GB/s
> 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> |                      |  running  |                  migrating                           |
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> | no mempress          |   4MB/s   |          8MB/s      (migrated success)               |
> -------------------------------------------------------------------------------------------
> | mempress 4096 1024   |  1060MB/s |     456MB/s ~ 1142MB/s (cpu throttle triggered)      |
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> | mempress 4096 4096   |  4114MB/s |     688MB/s ~ 4132MB/s (cpu throttle triggered)      |
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 
> Test dirtyrate by qmp command like this:
> 1.  virsh qemu-monitor-command [vmname] '{"execute":"calc-dirty-rate", "arguments": {"calc-time": [sleep-time]}}'; 
> 2.  sleep specific time which is a bit larger than sleep-time
> 3.  virsh qemu-monitor-command [vmname] '{"execute":"query-dirty-rate"}'

Thanks; it looks like we have a full set of reviews; I'll try and add
this for the next migration pull.

> The qmp command returns like this:
> {"return":{"status":"measured","dirty-rate":374,"start-time":3718293,"calc-time":1},"id":"libvirt-15"}
> 
> Further test dirtyrate by libvirt api like this:
> virsh getdirtyrate [vmname] [sleep-time]

So do you have some libvirt patches you're going to post?

Dave

> Chuan Zheng (12):
>   migration/dirtyrate: setup up query-dirtyrate framwork
>   migration/dirtyrate: add DirtyRateStatus to denote calculation status
>   migration/dirtyrate: Add RamblockDirtyInfo to store sampled page info
>   migration/dirtyrate: Add dirtyrate statistics series functions
>   migration/dirtyrate: move RAMBLOCK_FOREACH_MIGRATABLE into ram.h
>   migration/dirtyrate: Record hash results for each sampled page
>   migration/dirtyrate: Compare page hash results for recorded sampled
>     page
>   migration/dirtyrate: skip sampling ramblock with size below
>     MIN_RAMBLOCK_SIZE
>   migration/dirtyrate: Implement set_sample_page_period() and
>     is_sample_period_valid()
>   migration/dirtyrate: Implement calculate_dirtyrate() function
>   migration/dirtyrate: Implement
>     qmp_cal_dirty_rate()/qmp_get_dirty_rate() function
>   migration/dirtyrate: Add trace_calls to make it easier to debug
> 
>  migration/dirtyrate.c  | 426 +++++++++++++++++++++++++++++++++++++++++++++++++
>  migration/dirtyrate.h  |  70 ++++++++
>  migration/meson.build  |   2 +-
>  migration/ram.c        |  11 +-
>  migration/ram.h        |  10 ++
>  migration/trace-events |   8 +
>  qapi/migration.json    |  67 ++++++++
>  7 files changed, 583 insertions(+), 11 deletions(-)
>  create mode 100644 migration/dirtyrate.c
>  create mode 100644 migration/dirtyrate.h
> 
> -- 
> 1.8.3.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK