On 2/1/23 23:52, Adrian Hunter wrote:
On 1/02/23 20:06, Bart Van Assche wrote:
UFS devices perform better when using SYNCHRONIZE CACHE command
instead of the FUA flag. Hence this patch.
It would be nice to get some clarification on what is
going on for this case.
This includes with Data Reliability enabled?
In theory, WRITE+FUA should be at least as fast as
WRITE+SYNCHRONIZE CACHE, right?
Do we have any explanation for why that would not
be true?
In particular, is SYNCHRONIZE CACHE faster because
it is not, in fact, providing Reliable Writes?
Hi Adrian,
Setting the FUA bit in a WRITE command is functionally equivalent to
submitting a WRITE command without FUA and submitting a SYNCHRONIZE
CACHE command afterwards. For both sequences the storage device has to
guarantee that the written data will survive a sudden power loss event.
It is not clear to me why WRITE + SYNCHRONIZE CACHE is faster than WRITE
+ FUA. All I know is that this behavior has been observed for multiple
UFS devices from multiple vendors. I hope that one of the UFS vendors
can provide more information.
Bart.
