[Matrix]: don't specify #I/O threads by default.
[Matrix]: don't specify #I/O threads by default.

icoming/FlashGraph,flashxio/FlashX,icoming/FlashX,icoming/FlashX,icoming/FlashGraph,flashxio/FlashX,icoming/FlashGraph,flashxio/FlashX,flashxio/FlashX,icoming/FlashX,zheng-da/FlashX,zheng-da/FlashX,icoming/FlashGraph,icoming/FlashGraph,icoming/FlashX,zheng-da/FlashX,flashxio/FlashX,zheng-da/FlashX,flashxio/FlashX,zheng-da/FlashX,icoming/FlashX