Re: 2.6.20-rc2+: CFQ halving disk throughput.

[Tejun Heo]

Mark Lord wrote:
> Tejun Heo wrote:
>>
>> OT but care to make -i and -I work equivalently?  Such that -i reports
>> more detailed info and user can dump stored id block.
> 
> hdparm -I works just fine now.

No objection there.

> hdparm -i requires the HDIO_GET_IDENTITY ioctl() from drivers/ide,
> to retrieve the "boot time" copy of the identify block, before any
> mods are made by the driver.  But in recent years, drivers/ide has
> broken it, in that it tries to maintain the "boot time" copy in sync
> with the on-drive copy.  Kinda makes -i pointless.
> 
> Is there a way to retrieve the libata cached copy of the ID block?
> How?

Just implemented and posted patch for HDIO_GET_IDENTITY in an attempt to
access ATAPI IDENTIFY block using hdparm.

>> Support for IDENTIFY PACKET DEVICE would be nice too.
> 
> It already does that, using HDIO_DRIVE_CMD to retrieve it
> in the same way as for regular IDENTIFY DEVICE commands.

Hmmm... My hdparm doesn't seem to do that.

# hdparm -V
hdparm v6.9
# hdparm -I /dev/sr0

/dev/sr0:
 HDIO_DRIVE_CMD(identify) failed: Input/output error

Am I missing something?

> In hdparm-7.0, I'll have it use ATA passthrough when possible
> for most/all commands.

Glad to hear.

Happy new year.

-- 
tejun
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