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Re: [Qemu-devel] [PATCH 4/5] ram: Use MigrationStats for statistics
From: |
Peter Xu |
Subject: |
Re: [Qemu-devel] [PATCH 4/5] ram: Use MigrationStats for statistics |
Date: |
Wed, 7 Jun 2017 11:08:57 +0800 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Tue, Jun 06, 2017 at 07:33:45PM +0200, Juan Quintela wrote:
> Peter Xu <address@hidden> wrote:
> > On Mon, Jun 05, 2017 at 01:34:45PM +0100, Dr. David Alan Gilbert wrote:
> >> * Juan Quintela (address@hidden) wrote:
> >> > RAM Statistics need to survive migration to make info migrate work, so we
> >> > need to store them outside of RAMState. As we already have an struct
> >> > with those fields, just used them. (MigrationStats and XBZRLECacheStats).
> >> >
> >> > Signed-off-by: Juan Quintela <address@hidden>
> >>
> >> Hmm OK; this feels very much like it's the opposite of 180f61f from
> >> March; these variables keep moving around over the last couple of months
> >> - are they going to stay still now?
> >
> > O:-)
> >
> > Meanwhile, I don't know whether it'll be necessary to remove all the
> > functions like ram_bytes_transferred(), e.g., it would be just:
> >
> > uint64_t ram_bytes_transferred(void)
> > {
> > - return ram_state.bytes_transferred;
> > + return ram_counters.transferred;
> > }
> >
> > But I'm okay with either.
>
> That value was only used for filling the statistics. And we are filling
> a struct from another struct of the exact same type. Going through an
> exported function looks stranger.
>
> And as said in $commit, the idea was that creating a new counter was
> easy, right now you have to:
>
> - add it to MigrationParam (still have to do this)
> - add it to MigrationParams (still have to do this)
> - create the field in MigrationStats or RAMState
> - create a function that exports it
> - add that function in ram.h to export it
> - add it on qmp_query (still have to do this)
>
> So, we are moving from 6 steps to 3 steps. I think we are much better
> now, no? O:-)
Hmm, okay!
(as long as we won't move these functions back one day :-)
--
Peter Xu
- Re: [Qemu-devel] [PATCH 2/5] ram: Move ZERO_TARGET_PAGE inside XBZRLE, (continued)