misc/147227: SSD preformance issues

[Brandon Falk]

>Number:         147227
>Category:       misc
>Synopsis:       SSD preformance issues
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun May 30 18:10:06 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     Brandon Falk
>Release:        8.0-RELEASE
>Organization:
Gamozo
>Environment:
FreeBSD localhost 8.0-RELEASE FreeBSD 8.0-RELEASE #0: Sat Nov 21 15:02:08 UTC 2009     root at mason.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
I have an SSD that is rated at 285MB/s read, 275MB/s write, and 250MB/s sustained write. On Linux, I easily sustain all these speeds, but on FreeBSD I happen to only get about 108 MB/s write, and 116MB/s read. Another thing I noticed is that my drive is only running at SATA 150, even though my drive is SATA 300 and my controller is also detected as SATA 300.

*snip from dmesg*

atapci1: <Intel ICH7 SATA300 controller> port 0xc400-0xc407,0xc080-0xc083,0xc000-0xc007,0xbc00-0xbc03,0xb880-0xb88f irq 19 at device 31.2 on pci0
ad4: 47703MB <OCZ VERTEX2 1.00> at ata2-master SATA150

*snip from dmesg*

I do not have an AHCI setting in my BIOS, so that is not something that I can change, but still Linux happens to preform perfectly fine with the drive, so it has to be something to do with FreeBSD.
>How-To-Repeat:
Always occurs.
>Fix:
Unknown.

>Release-Note:
>Audit-Trail:
>Unformatted: