mmc: enable eMMC4.41 new feature background operations and HPI
cover mmc: enable eMMC4.41 new feature background operations and HPI
Hi,
These patches were enabled eMMC4.41 standard new feature: background operations and HPI.
Since these two features are opertional, driver only enable for those eMMC card which supports them.
HPI can interrupt both background operations and low priority foreground operations. In these patches, only implemented using HPI to interrupt background operations.
patch1: enable background operations feature for supported eMMC card.
patch2: let eMMC card do background operations when user reqeust queue is idle. In this patch, also considered when driver added runtime power management.
patch3: enable HPI feature for supported eMMC card.
patch4: use HPI to interrupt background operations if there is user request(foreground operations).
Thanks
Chuanxiao
Hi,
Basic question. Do you have any performance gain or improvement? In my test environment. no performance gain. Yes I know it's not for performance improvement.
How to measure or check it has some improvement?
Any ideas?
Thank you,
Kyungmin Park
Quoted 26 lines · Chuanxiao Dong
Hi,
These patches were enabled eMMC4.41 standard new feature: background operations and HPI.Since these two features are opertional, driver only enable for those eMMC card which supports them.
HPI can interrupt both background operations and low priority foreground operations. In these patches, only implemented using HPI to interrupt background operations.
patch1: enable background operations feature for supported eMMC card.
patch2: let eMMC card do background operations when user reqeust queue is idle. In this patch, also considered when driver added runtime power management.
patch3: enable HPI feature for supported eMMC card.
patch4: use HPI to interrupt background operations if there is user request(foreground operations).Thanks
Chuanxiao
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Quoted 4 lines
Basic question. Do you have any performance gain or improvement? In my test environment. no performance gain. Yes I know it's not for performance improvement.
My understanding:
If BKOPS feature is not enabled, the background operations will be started when card handles some read or write command. This will impact read/write performance. If BKOPS is enabled, driver can check whether need to do a BKOPS each time after card handled a read/write command. If need, driver can start BKOPS as soon as possible when user request is empty. This will can improve read/write performance. So I think, anyhow background operations can improve the performance, but only can be seen when your test card need to do a background operations. If your card needn't, there will be no performance gain I think. Driver will works as normal.
BTW, the BKOPS is an operational features for eMMC4.41 card, to ensure whether the card support this feature, check ext_csd[502].
Quoted 4 lines
How to measure or check it has some improvement?
Any ideas?
Right now I didn't know how to do a precise measurement. Maybe keep on transferring large data for a long time with a card which enabled/or not the BKOPS feature can help to get some measurement data.
Thanks
Chuanxiao