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

[Zheng Chuan]

On 2020/9/17 17:38, Dr. David Alan Gilbert wrote:
> * Zheng Chuan (zhengchuan@huawei.com) wrote:
>>
>>
>> On 2020/9/17 17:15, Dr. David Alan Gilbert wrote:
>>> * 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
>>>
>>
>> Hi, Dave.
>>
>> Yes, libvirt(including libvirt-python) interface will come after this qemu 
>> series patch:)
> 
> OK, great; please cc in jdenemar@redhat.com when you do.
> 
> Dave
> 
Sure, will post it asap:)

>>>> 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
>>>>
>>