[Hardware] DAC960 - " замирание " системы при записи

Alex Moskalenko mav на elserv.msk.su
Чт Авг 4 10:05:32 MSD 2005


Здравствуйте!

Столкнулся со следующей проблемой. При записи больших объемов данных система 
полностью замирает на 10-60 секунд. Не работают top, ps, отваливаются 
соединения samba. При этом успел заметить, что происходит это при активизации 
процесса bdflush. Ситуацию удается более-менее сгладить командой update -1 96 
-5 120, т.е. уменьшая количество одновременно сбрасываемых блоков на диски и 
уменьшая время возможного присутствия этих блоков в кэше. Полностью проблему 
это не решает, так как похоже на время операций ввода-вывода с контроллером 
система блокируется, что очень сильно отражается на обмене с сетью.

Кто-нибудь сталкивался с подобной проблемой? Куда можно копать?

Железо:
#lspci -v
00:00.0 Host bridge: Intel Corp. 82845 845 (Brookdale) Chipset Host Bridge 
(rev 03)
        Subsystem: Intel Corp. 82845 845 (Brookdale) Chipset Host Bridge
        Flags: bus master, fast devsel, latency 0
        Memory at d8000000 (32-bit, prefetchable) [size=64M]
        Capabilities: [e4] #09 [0104]
        Capabilities: [a0] AGP version 2.0

00:01.0 PCI bridge: Intel Corp. 82845 845 (Brookdale) Chipset AGP Bridge (rev 
03) (prog-if 00 [Normal decode])
        Flags: bus master, 66Mhz, fast devsel, latency 64
        Bus: primary=00, secondary=01, subordinate=01, sec-latency=32
        Memory behind bridge: e0000000-e1ffffff
        Prefetchable memory behind bridge: d0000000-d7ffffff

00:1e.0 PCI bridge: Intel Corp. 82801BA/CA/DB/EB/ER Hub interface to PCI 
Bridge (rev 12) (prog-if 00 [Normal decode])
        Flags: bus master, fast devsel, latency 0
        Bus: primary=00, secondary=02, subordinate=02, sec-latency=32
        I/O behind bridge: 0000c000-0000cfff
        Memory behind bridge: de000000-dfffffff
        Prefetchable memory behind bridge: dc000000-ddffffff

00:1f.0 ISA bridge: Intel Corp. 82801BA ISA Bridge (LPC) (rev 12)
        Flags: bus master, medium devsel, latency 0

00:1f.1 IDE interface: Intel Corp. 82801BA IDE U100 (rev 12) (prog-if 80 
[Master])
        Subsystem: Intel Corp.: Unknown device 2442
        Flags: bus master, medium devsel, latency 0
        I/O ports at f000 [size=16]

00:1f.2 USB Controller: Intel Corp. 82801BA/BAM USB (Hub #1) (rev 12) (prog-if 
00 [UHCI])
        Subsystem: Intel Corp. 82801BA/BAM USB (Hub #1)
        Flags: bus master, medium devsel, latency 0, IRQ 19
        I/O ports at d000 [size=32]

00:1f.3 SMBus: Intel Corp. 82801BA/BAM SMBus (rev 12)
        Subsystem: Intel Corp.: Unknown device 2442
        Flags: medium devsel, IRQ 17
        I/O ports at 5000 [size=16]

00:1f.4 USB Controller: Intel Corp. 82801BA/BAM USB (Hub #2) (rev 12) (prog-if 
00 [UHCI])
        Subsystem: Intel Corp.: Unknown device 2442
        Flags: bus master, medium devsel, latency 0, IRQ 23
        I/O ports at d800 [size=32]

00:1f.5 Multimedia audio controller: Intel Corp. 82801BA/BAM AC'97 Audio (rev 
12)
        Subsystem: Unknown device 414c:4710
        Flags: bus master, medium devsel, latency 0, IRQ 17
        I/O ports at dc00 [size=256]
        I/O ports at e000 [size=64]

01:00.0 VGA compatible controller: S3 Inc. Savage 4 (rev 04) (prog-if 00 
[VGA])
        Subsystem: S3 Inc. 86C394-397 Savage4
        Flags: bus master, 66Mhz, medium devsel, latency 248, IRQ 16
        Memory at e1000000 (32-bit, non-prefetchable) [size=512K]
        Memory at d0000000 (32-bit, prefetchable) [size=128M]
        Expansion ROM at <unassigned> [disabled] [size=64K]
        Capabilities: [dc] Power Management version 1
        Capabilities: [80] AGP version 2.0

02:01.0 Ethernet controller: D-Link System Inc Gigabit Ethernet Adapter (rev 
11)
        Subsystem: D-Link System Inc Gigabit Ethernet Adapter
        Flags: bus master, 66Mhz, medium devsel, latency 32, IRQ 21
        Memory at df000000 (32-bit, non-prefetchable) [size=16K]
        I/O ports at c000 [size=256]
        Expansion ROM at <unassigned> [disabled] [size=128K]
        Capabilities: [48] Power Management version 2
        Capabilities: [50] Vital Product Data

02:04.0 RAID bus controller: Mylex Corporation AcceleRAID 352/170/160 support 
Device (rev 02)
        Subsystem: Mylex Corporation: Unknown device 0052
        Flags: bus master, medium devsel, latency 32, IRQ 18
        Memory at dc000000 (32-bit, prefetchable) [size=32M]
        Expansion ROM at <unassigned> [disabled] [size=32K]
        Capabilities: [80] Power Management version 2
#cat /proc/interrupts
           CPU0
  0:    7100593    IO-APIC-edge  timer
  1:       2465    IO-APIC-edge  keyboard
  8:          2    IO-APIC-edge  rtc
  9:          0   IO-APIC-level  acpi
 12:         37    IO-APIC-edge  PS/2 Mouse
 14:         57    IO-APIC-edge  ide0
 18:     199537   IO-APIC-level  Mylex AcceleRAID 170
 19:          0   IO-APIC-level  usb-uhci
 21:   28155158   IO-APIC-level  SysKonnect SK-98xx
 23:          0   IO-APIC-level  usb-uhci
NMI:          0
LOC:    7100618
ERR:          0
MIS:          0
#cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 0
model name      : Intel(R) Pentium(R) 4 CPU 1300MHz
stepping        : 7
cpu MHz         : 1300.056
cache size      : 256 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : 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 ht tm
bogomips        : 2595.22
#cat /proc/rd/c0/current_status
***** DAC960 RAID Driver Version 2.4.11 of 11 October 2001 *****
Copyright 1998-2001 by Leonard N. Zubkoff <lnz на dandelion.com>
Configuring Mylex AcceleRAID 170 PCI RAID Controller
  Firmware Version: 7.02-00, Channels: 1, Memory Size: 32MB
  PCI Bus: 2, Device: 4, Function: 0, I/O Address: Unassigned
  PCI Address: 0xDC000000 mapped at 0xF8A0C000, IRQ Channel: 18
  Controller Queue Depth: 512, Maximum Blocks per Command: 2048
  Driver Queue Depth: 511, Scatter/Gather Limit: 128 of 257 Segments
  Physical Devices:
    0:0  Vendor: QUANTUM   Model: ATLAS_V_36_WLS    Revision: 0230
         Wide Synchronous at 160 MB/sec
         Serial Number: 143109651315
         Disk Status: Online, 71688192 blocks
    0:1  Vendor: QUANTUM   Model: ATLAS_V_36_WLS    Revision: 0230
         Wide Synchronous at 160 MB/sec
         Serial Number: 143110652586
         Disk Status: Online, 71688192 blocks
    0:2  Vendor: QUANTUM   Model: ATLAS_V_36_WLS    Revision: 0230
         Wide Synchronous at 160 MB/sec
         Serial Number: 143110652703
         Disk Status: Online, 71688192 blocks
    0:7  Vendor: MYLEX     Model: AcceleRAID 170    Revision: 0702
         Wide Synchronous at 160 MB/sec
         Serial Number:
  Logical Drives:
    /dev/rd/c0d0: RAID-5, Online, 143376384 blocks
                  Logical Device Initialized, BIOS Geometry: 255/63
                  Stripe Size: 64KB, Segment Size: 64KB
                  Read Cache Disabled, Write Cache Disabled
  No Rebuild or Consistency Check in Progress


Софт
#mount
/dev/rd/c0d0p1 on / type ext3 (rw)
proc on /proc type proc (rw,gid=19)
devpts on /dev/pts type devpts (rw,gid=5,mode=0620)
/dev/rd/c0d0p3 on /mnt/shared type xfs (rw)
/dev/hdb on /mnt/cdrom type subfs (ro,noexec,nosuid,nodev,fs=cdfss,kudzu)
/dev/fd0 on /mnt/floppy type subfs 
(rw,noexec,nosuid,nodev,sync,fs=floppyfss,kudzu)
usbfs on /proc/bus/usb type usbfs (rw)
#uname -a
Linux bdc.main.elserv.ru 2.4.26-std-up-alt12 #1 Thu May 12 14:53:58 MSD 2005 
i686 unknown unknown GNU/Linux
#cat /etc/altlinux-release
ALT Linux Master 2.4 (Citron)

Запись и чтение тестируются на разделе /dev/rd/c0d0p3 Включение на контроллере 
политики кэша Write Back (Становится Write Cache Enabled) проблемы не решает.

-- 
WBR, Alex Moskalenko


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