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Re: [Qemu-devel] [v7 09/14] migration: Make compression co-work with xbz
From: |
Li, Liang Z |
Subject: |
Re: [Qemu-devel] [v7 09/14] migration: Make compression co-work with xbzrle |
Date: |
Wed, 8 Apr 2015 13:52:15 +0000 |
> > Now, multiple thread compression can co-work with xbzrle. when xbzrle
> > is on, multiple thread compression will only work at the first round
> > of RAM data sync.
> >
> > Signed-off-by: Liang Li <address@hidden>
> > Signed-off-by: Yang Zhang <address@hidden>
> > Reviewed-by: Dr.David Alan Gilbert <address@hidden>
>
> Reviewed-by: Juan Quintela <address@hidden>
>
>
> > /* The empty QEMUFileOps will be used by file in CompressParam */
> > static const QEMUFileOps empty_ops = { };
> > +static bool compression_switch;
> > +
> > static DecompressParam *decomp_param; static QemuThread
> > *decompress_threads; static uint8_t *compressed_data_buf; @@ -436,6
> > +438,7 @@ void migrate_compress_threads_create(void)
> > if (!migrate_use_compression()) {
> > return;
> > }
> > + compression_switch = true;
> > thread_count = migrate_compress_threads();
> > compress_threads = g_new0(QemuThread, thread_count);
> > comp_param = g_new0(CompressParam, thread_count); @@ -1059,9
> > +1062,16 @@ static int ram_find_and_save_block(QEMUFile *f, bool
> last_stage,
> > block = QLIST_FIRST_RCU(&ram_list.blocks);
> > complete_round = true;
> > ram_bulk_stage = false;
> > + if (migrate_use_xbzrle()) {
> > + /* If xbzrle is on, stop using the data compression at
> > this
> > + * point. In theory, xbzrle can do better than
> > compression.
> > + */
> > + flush_compressed_data(f);
> > + compression_switch = false;
> > + }
>
> I still think that it should be better:
> a- don't mix them (or)
> b- if we mix them, just use compression always that we sent whole pages.
> if xbzrle is not able to compress a page, use compression after
> putting the page on the cache. i.e. try first to set through xbzrle,
> and if that don't work, use compression if possible (after zecond
> iteration, of course).)
>
>
> But as you are the one doing the code....
>
I prefer the b solution that you suggest, maybe I can send a patch later. But
now, I don't want to
make a big changes before the patch being merged.
Liang
> Later, Juan.
>
> PD. Yes, it can be changed later.
- [Qemu-devel] [v7 04/14] qemu-file: Add compression functions to QEMUFile, (continued)
- [Qemu-devel] [v7 04/14] qemu-file: Add compression functions to QEMUFile, Liang Li, 2015/04/08
- [Qemu-devel] [v7 02/14] migration: Add the framework of multi-thread compression, Liang Li, 2015/04/08
- [Qemu-devel] [v7 03/14] migration: Add the framework of multi-thread decompression, Liang Li, 2015/04/08
- [Qemu-devel] [v7 05/14] arch_init: Alloc and free data struct for compression, Liang Li, 2015/04/08
- [Qemu-devel] [v7 06/14] arch_init: Add and free data struct for decompression, Liang Li, 2015/04/08
- [Qemu-devel] [v7 07/14] migration: Split save_zero_page from ram_save_page, Liang Li, 2015/04/08
- [Qemu-devel] [v7 08/14] migration: Add the core code of multi-thread compression, Liang Li, 2015/04/08
- [Qemu-devel] [v7 09/14] migration: Make compression co-work with xbzrle, Liang Li, 2015/04/08
- [Qemu-devel] [v7 10/14] migration: Add the core code for decompression, Liang Li, 2015/04/08
- [Qemu-devel] [v7 11/14] migration: Add interface to control compression, Liang Li, 2015/04/08
- [Qemu-devel] [v7 12/14] migration: Use an array instead of 3 parameters, Liang Li, 2015/04/08