Dell/Perc5 raid/MPT SAS Integrated Raid Write Performance

[Tom Judge]

Filip Palian wrote:
> Hi folks,
> 
> I've also encountered problems with write performnce on PE860, below are
> some details.
> 
> 

I believe that a fix for this went into RELENG_6 this week.
Scott Long MFC'd the following fix at 2007-06-05 21:32:57.

Tom

Commit Message:

scottl      2007-06-03 23:13:05 UTC

   FreeBSD src repository

   Modified files:
     sys/dev/mpt          mpt.c mpt.h mpt_cam.c
   Log:
   mpt.c:
   mpt.h:
           Add support for reading extended configuration pages.
   mpt_cam.c:
           Do a top level topology scan on the SAS controller.  If any 
SATA device are discovered in this scan, send a passthrough FIS to set 
the write cache.  This is controllable through the following tunable at 
boot:
     hw.mpt.enable_sata_wc:
           -1 = Do not configure, use the controller default
            0 = Disable the write cache
            1 = Enable the write cache

           The default is -1.  This tunable is just a hack and may be
           deprecated in the future.

Turning on the write cache alleviates the write performance problems 
with SATA that many people have observed.  It is not recommend for those 
who value data reliability!  I cannot stress this strongly enough. 
However,  it is useful in certain circumstances, and it brings the 
performence in line with what a generic SATA controller running under 
the FreeBSD ATA driver provides (and the ATA driver has had the WC 
enabled by default for years).




> DELL PE860
> ==========
> 
> product:
> ========
> chipset LSI SAS 1068B0
> LSI SAS 1068-IR 06.50.00
> mptbios 6.06.00.02 (2006.04.05)
> 
> disks:
> ======
> 2x ST3160812AS in RAID1
> 
> dmesg:
> ======
> Copyright (c) 1992-2007 The FreeBSD Project.
> Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
>         The Regents of the University of California. All rights reserved.
> FreeBSD is a registered trademark of The FreeBSD Foundation.
> FreeBSD 6.2-RELEASE #4: Wed May 30 10:34:00 CEST 2007
>     root at ghostface1.expro.dmz:/usr/obj/usr/src/sys/GF-sn
> Timecounter "i8254" frequency 1193182 Hz quality 0
> CPU: Intel(R) Xeon(R) CPU           X3210  @ 2.13GHz (2133.42-MHz
> K8-class CPU)
>   Origin = "GenuineIntel"  Id = 0x6f7  Stepping = 7
> 
> Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
>   Features2=0xe3bd<SSE3,RSVD2,MON,DS_CPL,VMX,EST,TM2,<b9>,CX16,<b14>,<b15>>
>   AMD Features=0x20100800<SYSCALL,NX,LM>
>   AMD Features2=0x1<LAHF>
>   Cores per package: 4
> real memory  = 4831838208 (4608 MB)
> avail memory = 4130754560 (3939 MB)
> ACPI APIC Table: <DELL   PE_SC3  >
> ...
> mpt0: <LSILogic SAS/SATA Adapter> port 0xec00-0xecff mem
> 0xfe9fc000-0xfe9fffff,0xfe9e0000-0xfe9effff irq 16 at device 8.0 on pci2
> mpt0: [GIANT-LOCKED]
> mpt0: MPI Version=1.5.12.0
> mpt0: mpt_cam_event: 0x16
> mpt0: Unhandled Event Notify Frame. Event 0x16 (ACK not required).
> mpt0: mpt_cam_event: 0x12
> mpt0: Unhandled Event Notify Frame. Event 0x12 (ACK not required).
> mpt0: mpt_cam_event: 0x12
> mpt0: Unhandled Event Notify Frame. Event 0x12 (ACK not required).
> mpt0: mpt_cam_event: 0x16
> mpt0: Unhandled Event Notify Frame. Event 0x16 (ACK not required).
> mpt0: mpt_cam_event: 0xb
> mpt0: Unhandled Event Notify Frame. Event 0xb (ACK not required).
> da0 at mpt0 bus 0 target 0 lun 0
> 
> blogbench:
> ==========
> Frequency = 10 secs
> Scratch dir = [/var/tmp/]
> Spawning 3 writers...
> Spawning 1 rewriters...
> Spawning 5 commenters...
> Spawning 100 readers...
> Benchmarking for 30 iterations.
> The test will run during 5 minutes.
> ...
> 
> Final score for writes:            17
> Final score for reads :          2026
> 
> 
> 
> Currently I'm during upgrading firmware and applaying upgrades from
> Dell, if this will help I let you know.
> 
> Regards,
> Filip Palian
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