Re: [Qemu-devel] [PATCH 05/12] migration: show the statistics of compression

[Dr. David Alan Gilbert]

* Xiao Guangrong (address@hidden) wrote:
> 
> 
> On 06/14/2018 12:25 AM, Dr. David Alan Gilbert wrote:
>  }
> > >   static void migration_bitmap_sync(RAMState *rs)
> > > @@ -1412,6 +1441,9 @@ static void flush_compressed_data(RAMState *rs)
> > >           qemu_mutex_lock(&comp_param[idx].mutex);
> > >           if (!comp_param[idx].quit) {
> > >               len = qemu_put_qemu_file(rs->f, comp_param[idx].file);
> > > +            /* 8 means a header with RAM_SAVE_FLAG_CONTINUE. */
> > > +            compression_counters.reduced_size += TARGET_PAGE_SIZE - len 
> > > + 8;
> > 
> > I think I'd rather save just len+8 rather than than the subtraction.
> > 
> Hmmmmmm, is this what you want?
>       compression_counters.reduced_size += len - 8;
> 
> Then calculate the real reduced size in populate_ram_info() where we return 
> this
> info to the user:
>       info->compression->reduced_size = compression_counters.pages * 
> PAGE_SIZE - compression_counters.reduced_size;
> 
> Right?

I mean I'd rather see the actual size presented to the user rather than
the saving compared to uncompressed.

Dave

> > I think other than that, and Eric's comments, it's OK.
> > 
> 
> Thanks.
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK