Slower IDE performance with latest -ac kernels
Hi.
I'd mailed in a day or two ago a report about a problem with the 2.4.20-pre2-ac5 kernel. In that message there I'd said that the drives were running slower, but I had no numbers to back that up. Now I do. I just tried out the latest -ac kernel, and used my hdc drive to do some simple testing.
# hdparm -I /dev/hdc /dev/hdc:
ATA device, with non-removable media
Model Number: FUJITSU MPD3084AT Serial Number: 05043987 Firmware Revision: DD-03-47 Standards: Supported: 4 3 2 1 Likely used: 4 Configuration: Logical max current cylinders 16383 16383 heads 16 16 sectors/track 63 63 -- CHS current addressable sectors: 16514064 LBA user addressable sectors: 16514064 device size with M = 1024*1024: 8063 MBytes device size with M = 1000*1000: 8455 MBytes (8 GB)
Capabilities:
LBA, IORDY(cannot be disabled)
Buffer size: 512.0kB bytes avail on r/w long: 4 Queue depth: 1
Standby timer values: spec'd by Vendor
R/W multiple sector transfer: Max = 16 Current = 8
Advanced power management level: unknown setting (0x0000)
DMA: mdma0 mdma1 mdma2 udma0 udma1 *udma2 udma3 udma4
Cycle time: min=120ns recommended=120ns
PIO: pio0 pio1 pio2 pio3 pio4
Cycle time: no flow control=120ns IORDY flow control=120ns
Commands/features:
Enabled Supported:
READ BUFFER cmd
WRITE BUFFER cmd
Host Protected Area feature set
* Look-ahead
Write cache
Power Management feature set
Security Mode feature set
* SMART feature set
Advanced Power Management feature set
Security:
supported
not enabled
not locked
not frozen
not expired: security count
not supported: enhanced erase
24min for SECURITY ERASE UNIT.
Using kernel 2.4.20-pre4-ac1 ...
# hdparm /dev/hdc /dev/hdc: multcount = 8 (on) IO_support = 3 (32-bit w/sync) unmaskirq = 0 (off) using_dma = 0 (off) keepsettings = 0 (off) readonly = 0 (off) readahead = 8 (on) geometry = 1027/255/63, sectors = 16514064, start = 0
# cat /proc/ide/hdc/settings name value min max mode ---- ----- --- --- ---- acoustic 0 0 254 rw address 0 0 2 rw bios_cyl 1027 0 65535 rw bios_head 255 0 255 rw bios_sect 63 0 63 rw breada_readahead 8 0 255 rw bswap 0 0 1 r current_speed 0 0 70 rw failures 0 0 65535 rw file_readahead 124 0 16384 rw init_speed 0 0 70 rw io_32bit 3 0 3 rw keepsettings 0 0 1 rw lun 0 0 7 rw max_failures 1 0 65535 rw max_kb_per_request 128 1 255 rw multcount 8 0 16 rw nice1 1 0 1 rw nowerr 0 0 1 rw number 2 0 3 rw pio_mode write-only 0 255 w slow 0 0 1 rw unmaskirq 0 0 1 rw using_dma 0 0 1 rw wcache 0 0 1 rw
# hdparm -tT /dev/hdc
/dev/hdc:
Timing buffer-cache reads: 128 MB in 2.81 seconds = 45.55 MB/sec
Timing buffered disk reads: 64 MB in 59.40 seconds = 1.08 MB/sec
Using kernel 2.4.20-pre2-ac2 ...
# hdparm /dev/hdc /dev/hdc: multcount = 8 (on) IO_support = 3 (32-bit w/sync) unmaskirq = 0 (off) using_dma = 0 (off) keepsettings = 0 (off) readonly = 0 (off) readahead = 8 (on) geometry = 1027/255/63, sectors = 16514064, start = 0
# cat /prod/ide/hdc/settings name value min max mode ---- ----- --- --- ---- acoustic 0 0 254 rw address 0 0 2 rw bios_cyl 1027 0 65535 rw bios_head 255 0 255 rw bios_sect 63 0 63 rw breada_readahead 8 0 255 rw bswap 0 0 1 r current_speed 0 0 70 rw failures 0 0 65535 rw file_readahead 124 0 16384 rw ide_scsi 0 0 1 rw init_speed 0 0 70 rw io_32bit 3 0 3 rw keepsettings 0 0 1 rw lun 0 0 7 rw max_failures 1 0 65535 rw max_kb_per_request 128 1 255 rw multcount 8 0 16 rw nice1 1 0 1 rw nowerr 0 0 1 rw number 2 0 3 rw pio_mode write-only 0 255 w slow 0 0 1 rw unmaskirq 0 0 1 rw using_dma 0 0 1 rw wcache 0 0 1 rw
# hdparm -tT /dev/hdc
/dev/hdc:
Timing buffer-cache reads: 128 MB in 2.89 seconds = 44.29 MB/sec
Timing buffered disk reads: 64 MB in 7.06 seconds = 9.07 MB/sec
The disk reads are significantly faster under the older kernel, which I'm using right now.
I tried the suggestion Andre Hedrick posted ...
# echo max_kb_per_request:256 > /proc/ide/hdc/settings
... and it made no difference. In fact, the max_kb_per_request line didn't change at all. The value is larger than the "max" column value, but his mail said that 255 wasn't correct. ?????
I can't use DMA on either drive on this machine, as it doesn't work. I've never found the magic BIOS bits to see what can be set to activate that feature, so using the 'hdparm -d1' command won't work here. I've also been burned once using hdparm, so I'm hesistant to try flags the man page says can cause problems, such as the irq unmasking option '-u'.
Here's a little more info that might be useful ...
# lspci -vv
00:00.0 Host bridge: Acer Laboratories Inc. [ALi] M1531 [Aladdin IV] (rev b3)
Subsystem: Acer Laboratories Inc. [ALi] M1531 [Aladdin IV]
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
Status: Cap- 66Mhz- UDF- FastB2B- ParErr- DEVSEL=slow >TAbort- <TAbort- <MAbort+ >SERR- <PERR-
Latency: 32
00:02.0 ISA bridge: Acer Laboratories Inc. [ALi] M1533 PCI to ISA Bridge [Aladdin IV] (rev b4)
Control: I/O+ Mem+ BusMaster+ SpecCycle+ MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
Status: Cap- 66Mhz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort+ <MAbort+ >SERR- <PERR-
Latency: 0
00:05.0 VGA compatible controller: S3 Inc. ViRGE/DX or /GX (rev 01) (prog-if 00 [VGA])
Subsystem: S3 Inc. ViRGE/DX
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
Status: Cap- 66Mhz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
Latency: 64 (1000ns min, 63750ns max)
Interrupt: pin A routed to IRQ 0
Region 0: Memory at ec000000 (32-bit, non-prefetchable) [size=64M]
Expansion ROM at ebff0000 [disabled] [size=64K]
00:0b.0 IDE interface: Acer Laboratories Inc. [ALi] M5229 IDE (rev 20) (prog-if fa)
Control: I/O+ Mem- BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
Status: Cap- 66Mhz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
Latency: 32 (500ns min, 1000ns max)
Interrupt: pin A routed to IRQ 14
Region 0: [virtual] I/O ports at 01f0
Region 1: [virtual] I/O ports at 03f4
Region 2: [virtual] I/O ports at 0170
Region 3: [virtual] I/O ports at 0374
Region 4: I/O ports at ffa0 [size=16]
Art Haas
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