Re: [Qemu-devel] [PATCH] hmp/info_migration: formatting migration capability output

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

* Wei Yang (richardw.yang@linux.intel.com) wrote:
> On Fri, Aug 02, 2019 at 07:24:34AM +0200, Markus Armbruster wrote:
> >Subject doesn't quite conform to conventions.  Suggest
> >
> >    hmp: Improve how "info migrate" formats capabilities
> 
> Thanks
> 
> >
> >Wei Yang <richardw.yang@linux.intel.com> writes:
> >
> >> Current we put all migration capability in one line, which make it hard
> >> to read them and someone them are missed due to terminal width.
> >>
> >> This patch formats it to print 4 in one line, which looks like this now:
> >>
> >> capabilities:
> >>               xbzrle: off         rdma-pin-all: off        auto-converge: off          zero-blocks: off
> >>             compress:  on               events: off         postcopy-ram: off               x-colo: off
> >>          release-ram: off                block: off          return-path: off pause-before-switchover: off
> >>              multifd: off        dirty-bitmaps: off   postcopy-blocktime: off  late-block-activate: off
> >>      x-ignore-shared: off
> >>
> >> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
> >> ---
> >>  monitor/hmp-cmds.c | 8 ++++++--
> >>  1 file changed, 6 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
> >> index 5ca3ebe942..29ce5b73e4 100644
> >> --- a/monitor/hmp-cmds.c
> >> +++ b/monitor/hmp-cmds.c
> >> @@ -229,9 +229,13 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
> >>  
> >>      /* do not display parameters during setup */
> >>      if (info->has_status && caps) {
> >> +        int index = 0;
> >>          monitor_printf(mon, "capabilities: ");
> >> -        for (cap = caps; cap; cap = cap->next) {
> >> -            monitor_printf(mon, "%s: %s ",
> >> +        for (cap = caps; cap; cap = cap->next, index++) {
> >> +            if (!(index % 4)) {
> >> +                monitor_printf(mon, "\n");
> >> +            }
> >> +            monitor_printf(mon, "%20s: %3s ",
> >>                             MigrationCapability_str(cap->value->capability),
> >>                             cap->value->state ? "on" : "off");
> >>          }
> >
> >This assumes migration capability names are at most 20 characters long.
> >late-block-activate is pushing it already: 19 characters.
> >
> >It adds up to 104 characters per line, which is rather wide.
> >
> >What about putting each capability on its own line, just like globals,
> >and just like "info migrate_capabilities"?
> >
> >(qemu) info migrate
> >globals:
> >store-global-state: on
> >only-migratable: off
> >send-configuration: on
> >send-section-footer: on
> >decompress-error-check: on
> >clear-bitmap-shift: 18
> >capabilities:
> >xbzrle: off
> >rdma-pin-all: off
> >auto-converge: off
> >[...]
> 
> This looks good, while would reader may feel difficult to clarify from which
> one the capabilities stops. 
> 
> How about add 4 space at the beginning of each capability?
> 
> Would the output be too long? How about wrap two capability into one line?

IMHO the simpler way is just not to display the capabilities on
'info migrate' at all.  If people want the list of capabilities there's
already 'info migrate_capabiltiies' they can use.

It was nice displaying them at the start of 'info migrate'
when we only had a few, but nowe we've got so many it's perhaps
easier just to omit them.

Dave

> -- 
> Wei Yang
> Help you, Help me
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK