Re: Linux 2.6.29

Re: Linux 2.6.29

[Jeff Garzik]

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

Re: Linux 2.6.29

[Mark Lord]

Jeff Garzik wrote:
> Ric Wheeler wrote:
>> Jeff Garzik wrote:
>>> Jens Axboe wrote:
..
>>> 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...
..

Speaking of which.. you probably won't see the preliminary rev
of sata_mv + target_mode until sometime this weekend.

It's going to be something quite simple for 2.6.30,
and we can expand on that in later kernels.

Cheers