Re: Linux 2.6.29

Jeff Garzik
2009-03-31T22:23:26Z

Ric Wheeler wrote:
> Jeff Garzik wrote:
>> Jens Axboe wrote:
>>> Another problem is that FLUSH_CACHE sucks. Really. And not just on
>>> ext3/ordered, generally. Write a 50 byte file, fsync, flush cache and
>>> wit for the world to finish. Pretty hard to teach people to use a nicer
>>> fdatasync(), when the majority of the cost now becomes flushing the
>>> cache of that 1TB drive you happen to have 8 partitions on. Good luck
>>> with that.
>>
>> (responding to an email way back near the start of the thread)
>>
>> I emailed Microsoft about their proposal to add a WRITE BARRIER
>> command to ATA, documented at
>> http://www.t13.org/Documents/UploadedDocuments/docs2007/e07174r0-Write_Barrier_Command_Proposal.doc

>> The MSFT engineer said they were definitely still pursuing this proposal.
>>
>> IMO we could look at this too, or perhaps come up with an alternate
>> proposal like FLUSH CACHE RANGE(s).

> I agree that it is worth getting better mechanisms in place - the cache
> flush is really primitive. Now we just need a victim to sit in on
> T13/T10 standards meetings :-)

Heck, we could even do a prototype implementation with the help of Mark
Lord's sata_mv target mode support...

Jeff