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

[Dr. David Alan Gilbert]

* 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

> >> 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