Re: [PATCH v2 2/2] migration/hmp: Add "info migrate -a", reorg the dump

[Peter Xu <peterx@redhat.com>]

On Thu, May 22, 2025 at 12:55:05AM +0000, Zhijian Li (Fujitsu) wrote:
> 
> 
> On 22/05/2025 05:04, Dr. David Alan Gilbert wrote:
> > * Peter Xu (peterx@redhat.com) wrote:
> >> On Wed, May 21, 2025 at 08:43:37AM +0000, Zhijian Li (Fujitsu) wrote:
> >> [...]
> >>>> After this change, sample output (default, no "-a" specified):
> >>>>
> >>>>     Status: postcopy-active
> >>>>     Time (ms): total=40504, setup=14, down=145
> >>>>     RAM info:
> >>>>       Bandwidth (mbps): 6102.65
> >>>>       Sizes (KB): psize=4, total=16777992
> >>>>         transferred=37673019, remain=2136404,
> >>>>         precopy=3, multifd=26108780, postcopy=11563855
> >>>>       Pages: normal=9394288, zero=600672, rate_per_sec=185875
> >>>>       Others: dirty_syncs=3, dirty_pages_rate=278378, postcopy_req=4078
> >>>
> >>> (Feel free to ignore my comment if you have reached a consensus.)
> >>>
> >>> Putting multiple fields in one line is a true need for human reading?
> >>
> >> It definitely helps me but I agree that can be subjective.  So I'm happy to
> >> collect opinions.
> >>
> >> So my above layout was trying to leverage more on screens where width is
> >> bigger than the height (which is pretty much the default).
> > 
> > I think perhaps the problem with the on-one-line layout is that the grouping
> > is wrong;  grouping by unit probably doesn't make sense.
> > 
> > So it makes sense to me to have:
> >     Sizes: psize=4/KB
> >     Transfer: total=16777992 kB transferred=37673019 kB remain=11563855 kB
> >     Pages: normal=9394288 zero=600672
> >     Page rates: transferred=185875/s dirtied=278378/s
> >     Other: dirty_sync=3 postcopy_req=4078
> 
> 
> Oh, I vote this !!, more clear to me.

I followed up with Dave's idea, but then added all entries into it, below.

  Status: postcopy-active
  Time (ms): total=40504, setup=14, down=145
  RAM info:
    Throughput (Mbps): 6102.65
    Sizes (KiB):        pagesize=4, total=16777992
    Transfers (KiB):    transferred=37673019, remain=2136404
      Channels (KiB):   precopy=3, multifd=26108780, postcopy=11563855
      Page Types:       normal=9394288, zero=600672
    Page Rates (pps):   transfer_rate=185875, dirty_rate=278378
    Others:             dirty_syncs=3, postcopy_req=4078

Logically I should have moved "Throughput" out, because that should also
include all other things (non-ram iterators, device states).  But currently
it's an entry under info->ram.. so I kept it there.

It also has the "total" in "Sizes" to make the next line shorter
(meanwhile, "total" is also a constant size like "psize"), the hope is it's
still close enough to read when reading "Transfers" on the next line.

I also provided further indents to "Channels" and "Page Types" because they
should be taken as sub-class of "Transfer".

How is this?  Since we're at it, I can send a follow up patch after we
reach a consensus (I may also include that in another series where I'll
further add things into HMP; I'm looking at making blocktime to report page
latencies too).

-- 
Peter Xu