lee writes:
> "Wolfgang S. Rupprecht" writes:
>> The SSD in question is capable of 550 MByte/sec (Intel 520 SSD), while
>> the PCIE controller is only an x1 single lane controller which probbly
>> saturates the single lane at 480 MByte/sec. I'm assuming (perhaps
>> incorrectly) that the control
"Wolfgang S. Rupprecht" writes:
> Alan Cox writes:
>> On Thu, 08 Nov 2012 09:43:29 -0800
>> "Wolfgang S. Rupprecht" wrote:
>>> Can someone familiar with how the AHCI driver works confirm that data
>>> overruns on a SATA link can cause the driver to down-shift the SATA
>>> speed 6->3->1.5 Gbits/
> saturates the single lane at 480 MByte/sec. I'm assuming (perhaps
> incorrectly) that the controller is choking when it receives more data
> from the SATA than it can transmit on the PCIE.
The link has hardware flow control, whether the end result of saturating
the link is poorer performance th
Alan Cox writes:
> On Thu, 08 Nov 2012 09:43:29 -0800
> "Wolfgang S. Rupprecht" wrote:
>> Can someone familiar with how the AHCI driver works confirm that data
>> overruns on a SATA link can cause the driver to down-shift the SATA
>> speed 6->3->1.5 Gbits/sec. I don't see any kprintf's but I no
On Thu, 08 Nov 2012 09:43:29 -0800
"Wolfgang S. Rupprecht" wrote:
>
> Can someone familiar with how the AHCI driver works confirm that data
> overruns on a SATA link can cause the driver to down-shift the SATA
> speed 6->3->1.5 Gbits/sec. I don't see any kprintf's but I notice that
> a high spe
Can someone familiar with how the AHCI driver works confirm that data
overruns on a SATA link can cause the driver to down-shift the SATA
speed 6->3->1.5 Gbits/sec. I don't see any kprintf's but I notice that
a high speed SSD acting as if the SATA were running at 1.5 Gbits/sec.
This looks like i
