Messages in this thread | | | Date | Thu, 18 Nov 2010 17:07:02 -0500 | From | Mark Lord <> | Subject | Re: [PATCH 1/2] fs: Do not dispatch FITRIM through separate super_operation |
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On 10-11-18 04:50 PM, James Bottomley wrote: > > Before we go gung ho on this, there's no evidence that N discontiguous > ranges in one command are any better than the ranges sent N times ... > the same amount of erase overhead gets sent on SSDs.
No, we do have evidence: execution time of the TRIM commands on the SSD.
The one-range-at-a-time is incredibly slow compared to multiple ranges at a time. That slowness comes from somewhere, with about 99.9% certainty that it is due to the drive performing slow flash erase cycles.
I think perhaps we should do the batching as much as possible, and then split them into single ranges for LLDs that cannot handle multi-ranges.
Way more efficient that way.
Cheers
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