Systems and methods for managing bias mode switching
A storage device is disclosed. The storage device may include a storage for a data and a controller to manage access to the data in the storage. A mechanism may automatically manage a bias mode for a chunk of the data in the storage, the bias mode including one of a host bias mode and a device bias mode.
1. A storage device, comprising:
a storage media for a data;
a controller to manage access to the data in the storage media; and
a mechanism to store and manage a bias score and a bias mode for a chunk of the data in the storage media based at least in part on the bias score, the bias mode including one of a host bias mode and a device bias mode, the bias score including a multi-bit counter to track access of the chunk of the data in the storage media from a host processor or a device.
2. The storage device according to claim 1 , wherein the mechanism to store and manage the bias mode for the chunk of the data in the storage media is configured to issue one of an invalidate request or a back invalidate request to the host processor for the chunk of the data in the storage media based at least in part on the bias mode for the chunk of the data in the storage media being switched to the device bias mode.
3. The storage device according to claim 1 , wherein the mechanism to store and manage the bias score and the bias mode for the chunk of the data in the storage media includes the bias score and the bias score for the chunk of the data in the storage media.
4. The storage device according to claim 3 , wherein the mechanism to store and manage the bias score and the bias mode for the chunk of the data in the storage media is configured to adjust the bias score for the chunk of the data in the storage media based at least in part on an access of the chunk of the data in the storage media by one of the device or the host processor.
5. The storage device according to claim 3 , wherein the mechanism to store and manage the bias score and the bias mode for the chunk of the data in the storage media is configured to change the bias mode for the chunk of the data in the storage media to the host bias mode based at least in part on the bias score reaching a first threshold, and to change the bias mode for the chunk of the data in the storage media to the device bias mode based at least in part on the bias score reaching a second threshold.
6. The storage device according to claim 1 , wherein the mechanism to store and manage the bias score and the bias mode for the chunk of the data in the storage media is configured to store and manage the bias score and the bias mode for the chunk of the data in the storage media based at least in part on the device accessing a second chunk of the data in the storage media.
7. The storage device according to claim 6 , wherein:
the second chunk of the data in the storage media includes a first page;
the chunk of the data in the storage media includes a second page;
the mechanism to store and manage the bias score and the bias mode for the chunk of the data in the storage media is configured to further store and manage a second bias score and a second bias mode for the second chunk of the data in the storage media; and
the mechanism to store and manage the bias score and the bias mode for the chunk of the data in the storage media is configured to store and manage bias score and the bias mode for the chunk of the data in the storage media based at least in part on the fact that the second page is contiguous to the first page.
8. The storage device according to claim 1 , wherein the mechanism to store and manage the bias score and the bias mode for the chunk of the data in the storage media includes a snoop filter including an entry for the chunk of the data in the storage media as accessed by the host processor, the snoop filter further including a cache controller.
9. The storage device according to claim 8 , wherein:
the entry for the chunk of the data in the storage media identifies that the chunk of the data in the storage media is unmodified by the host processor; and
the mechanism to store and manage the bias mode for the chunk of the data in the storage media is configured to invalidate the chunk of the data in the storage media from a cache of the host processor based at least in part on the snoop filter evicting the entry for the chunk of the data in the storage media.
10. The storage device according to claim 8 , wherein:
the entry for the chunk of the data in the storage media identifies that the chunk of the data in the storage media is modified by the host processor; and
the mechanism to store and manage the bias score and the bias mode for the chunk of the data in the storage media is configured to back-invalidate the chunk of the data in the storage media from a cache of the host processor based at least in part on the snoop filter evicting the entry for the chunk of the data in the storage media.
11. The storage device according to claim 1 , wherein the multi-bit counter includes at least two bits.
12. A method, comprising:
receiving, at a storage device, a request to access a chunk of a data in a storage media of the storage device, the request received from a source;
identifying a bias score for the chunk of the data stored in the storage media of the storage device, the bias score including a multi-bit counter to track access of the chunk of the data in the storage media from a host processor or a device, the storage media of the storage device further storing a bias mode for the chunk of the data, the bias mode based at least in part on the bias score; and
adjusting the bias score for the chunk of the data in the storage media of the storage device based at least in part on the source of the request.
13. The method according to claim 12 , wherein:
receiving, at the storage device, the request to access the chunk of the data in the storage media of the storage device includes receiving, at the storage device, the request to access the chunk of the data in the storage media of the storage device, the request received from the host processor; and
adjusting the bias score for the chunk of the data in the storage media of the storage device based at least in part on the source of the request includes incrementing the bias score for the chunk of the data in the storage media of the storage device based at least in part on the source including the host processor.
14. The method according to claim 13 , further comprising switching the bias mode for the chunk of the data in the storage media of the storage device to a host bias mode based at least in part on the bias score crossing a threshold.
15. The method according to claim 12 , wherein:
receiving, at the storage device, the request to access the chunk of the data in the storage media of the storage device includes receiving, at the storage device, the request to access the chunk of the data in the storage media of the storage device, the request received from the device; and
adjusting the bias score for the chunk of the data in the storage media of the storage device based at least in part on the source of the request includes decrementing the bias score for the chunk of the data in the storage media of the storage device based at least in part on the source including the device.
16. The method according to claim 15 , further comprising switching the bias mode for the chunk of the data in the storage media of the storage device to a device bias mode based at least in part on the bias score crossing a threshold.