On Thu, Mar 23, 2017 at 09:45:30PM +0100, Juan Quintela wrote:
> Rename it to preffer_xbzrle that is a more descriptive name.
s/preffer/prefer/?
>
> Signed-off-by: Juan Quintela <quint...@redhat.com>
> ---
> migration/ram.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index 6a39704..591cf89 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -217,6 +217,9 @@ struct RAMState {
> uint64_t dirty_pages_rate;
> /* Count of requests incoming from destination */
> uint64_t postcopy_requests;
> + /* Should we move to xbzrle after the 1st round
> + of compression */
> + bool preffer_xbzrle;
> /* protects modification of the bitmap */
> QemuMutex bitmap_mutex;
> /* Ram Bitmap protected by RCU */
> @@ -335,7 +338,6 @@ static QemuCond comp_done_cond;
> /* 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 QemuMutex decomp_done_lock;
> @@ -419,7 +421,6 @@ 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);
> @@ -1091,7 +1092,7 @@ static bool find_dirty_block(RAMState *rs,
> PageSearchStatus *pss,
> * point. In theory, xbzrle can do better than compression.
> */
> flush_compressed_data(rs);
> - compression_switch = false;
> + rs->preffer_xbzrle = true;
> }
> }
> /* Didn't find anything this time, but try again on the new block */
> @@ -1323,7 +1324,7 @@ static int ram_save_target_page(RAMState *rs,
> MigrationState *ms,
> /* Check the pages is dirty and if it is send it */
> if (migration_bitmap_clear_dirty(rs, dirty_ram_abs)) {
> unsigned long *unsentmap;
> - if (compression_switch && migrate_use_compression()) {
> + if (!rs->preffer_xbzrle && migrate_use_compression()) {
IIUC this prefer_xbzrle can be dynamically calculated by existing
states:
static inline bool ram_compression_active(RAMState *rs)
{
/*
* If xbzrle is on, stop using the data compression after first
* round of migration even if compression is enabled. In theory,
* xbzrle can do better than compression.
*/
return migrate_use_compression() && \
(rs->ram_bulk_stage || !migrate_use_xbzrle());
}
Then this line can be written as:
if (ram_compression_active(rs)) {
And if so, we can get rid of prefer_xbzrle, right?
Having prefer_xbzrle should be slightly faster though, since it'll at
least cache the above calculation.
Thanks,
> res = ram_save_compressed_page(rs, ms, pss, last_stage);
> } else {
> res = ram_save_page(rs, ms, pss, last_stage);
> --
> 2.9.3
>
>
-- peterx
