Re: Cannot enable DMA on SATA drive (SCSI-libsata, VIA SATA)
From: Gianluca Cecchi
Date: Tue Oct 05 2004 - 19:32:54 EST
Hello,
please CC me to your replies as I'm not currently a subscriber; thanks in
advance.
Excuse me for the long text: it contains information about behaviour of
my system.
This thread had no news about 1) dma settings considerations and 2) heavy
cpu load during
heavy I/O operations 3) summary on performance/smartness of system.
My system is a Dual Athlon 1800MHz with 1Gb of ram.
There are 2xsata disks (Maxtor 6Y120M0 120Gb each) and I have a Magnex KW571S
PCI ATA RAID card, that is based on Sil Image 3112a chipset (two indipendent
sata
channels).
I'm not planning to use the raid provided by the card.
My os is a Slackware 10.0 upgraded to -current (01/10/04) with kernel.org
2.6.8.1
kernel.
Eventually I can provide config. Btw, I'm using udev and kernel preemption.
The os was transferred and LILO reinstalled from a previous 18Gb scsi disk.
At this moment I'm using only the first sata disk.
Output of my dmesg is:
libata version 1.02 loaded.
sata_sil version 0.54
ACPI: PCI interrupt 0000:00:08.0[A] -> GSI 16 (level, low) -> IRQ 177
ata1: SATA max UDMA/100 cmd 0xF8811080 ctl 0xF881108A bmdma 0xF8811000 irq
177
ata2: SATA max UDMA/100 cmd 0xF88110C0 ctl 0xF88110CA bmdma 0xF8811008 irq
177
ata1: dev 0 cfg 49:2f00 82:7c6b 83:7b09 84:4003 85:7c69 86:3a01 87:4003
88:207f
ata1: dev 0 ATA, max UDMA/133, 240121728 sectors:
ata1: dev 0 configured for UDMA/100
scsi2 : sata_sil
ata2: dev 0 cfg 49:2f00 82:7c6b 83:7b09 84:4003 85:7c69 86:3a01 87:4003
88:207f
ata2: dev 0 ATA, max UDMA/133, 240121728 sectors:
ata2: dev 0 configured for UDMA/100
scsi3 : sata_sil
Vendor: ATA Model: Maxtor 6Y120M0 Rev: YAR5
Type: Direct-Access ANSI SCSI revision: 05
Vendor: ATA Model: Maxtor 6Y120M0 Rev: YAR5
Type: Direct-Access ANSI SCSI revision: 05
SCSI device sda: 240121728 512-byte hdwr sectors (122942 MB)
SCSI device sda: drive cache: write back
sda: sda1 sda2 sda3 sda4 < sda5 >
Attached scsi disk sda at scsi2, channel 0, id 0, lun 0
SCSI device sdb: 240121728 512-byte hdwr sectors (122942 MB)
SCSI device sdb: drive cache: write back
sdb: sdb1 sdb2 sdb3 sdb4 < sdb5 >
Attached scsi disk sdb at scsi3, channel 0, id 0, lun 0
Point 1)
Jeff Garzik confirmed that DMA is always enabled when sata drives are seen
as
scsi devices.
But do I have to worry or not about the lines
ata1: SATA max UDMA/100 cmd 0xF8811080 ctl 0xF881108A bmdma 0xF8811000 irq
177
...
ata1: dev 0 ATA, max UDMA/133, 240121728 sectors:
ata1: dev 0 configured for UDMA/100
and the same for ata2?
Shouldn't I see max UDMA/133 for the controller, instead of 100?
I have also an IDE disk in the system.
hdparm -i on it gives:
/dev/hdb:
Model=SAMSUNG SP0411N, FwRev=TW100-07, SerialNo=0611J1AW931372
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
RawCHS=16383/16/63, TrkSize=34902, SectSize=554, ECCbytes=4
BuffType=DualPortCache, BuffSize=2048kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=66055248
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5
AdvancedPM=no WriteCache=enabled
Drive conforms to: (null):
Does this interfere in some way with sata disk udma settings?
I'm not able to detach it at the moment, but as soon as I can, I'll let
you know
eventually.
Point 2)
As Petr Sebor, I also have serious problems when doing heavy I/O, especially
in read operations. Any hints?
My hdparm -tT values are good, I think:
hdparm -tT /dev/sda
/dev/sda:
Timing cached reads: 960 MB in 2.00 seconds = 479.59 MB/sec
Timing buffered disk reads: 170 MB in 3.00 seconds = 56.62 MB/sec
When doing:
time dd if=/dev/sda of=/dev/null bs=1024k count=4096
4096+0 records in
4096+0 records out
real 1m12.378s
user 0m0.029s
sys 0m21.280s
So confirmed the 56MB/s reading.
But taking in parallel top with refresh 1s in another window, during the
80
seconds elapsed above, I had two freezes in top session: one of 20sec and
another
of 15 sec: about the half of the time of the total I/O operation!
During this time there was one cpu used at about 30%, no other cpu constraints.
I repeated the operation with similar behaviour. Sometimes also 50 contiguos
secs
of freeze, until I/O operation finished.
The freeze is not about all system itself, but only certian things.
For example I tried also a vmstat session in another window with 3secs of
delay
and it had no problems while top was blocked:
gcecchi@tkamd:~$ vmstat 3
procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy
id wa
0 2 4360 87100 737100 53728 0 0 58283 0 2223 2726 0 19
45 36
1 1 4360 87036 737128 53768 0 0 58197 5 2227 2655 0 19
46 35
0 2 4360 86128 738148 53700 0 0 58240 0 2232 2677 0 19
47 35
0 2 4360 86048 738156 53760 0 0 58283 1 2228 2391 1 19
45 36
1 2 4360 86332 737928 53716 0 0 58197 0 2233 2434 1 19
47 34
0 2 4360 86524 737708 53800 0 0 58283 0 2343 2662 1 19
46 34
0 3 4360 87036 737244 53788 0 0 57603 0 2243 2483 1 19
46 34
0 1 4360 86252 738032 53748 0 0 57429 7 2232 2482 1 18
46 35
0 1 4360 87220 737024 53804 0 0 58197 3 2159 2205 2 18
48 33
0 2 4360 86012 738292 53692 0 0 58240 29 2212 2401 1 19
48 32
1 1 4360 86256 738036 53744 0 0 58325 0 2249 2643 0 19
47 34
0 2 4360 86956 737304 53796 0 0 58197 0 2226 2727 0 19
46 35
0 2 4360 87148 737092 53736 0 0 58240 0 2255 2748 0 19
45 36
0 2 4360 87284 736900 53724 0 0 58283 3 2299 2995 2 19
45 34
2 1 4360 86772 737440 53796 0 0 57097 0 2506 3284 2 20
42 36
0 2 4360 86700 737572 53732 0 0 57771 1 2324 3290 2 20
43 35
0 2 4360 86428 737780 53796 0 0 57899 0 2271 3002 2 19
45 34
2 3 4360 86748 737464 53772 0 0 58284 0 2237 2764 1 18
47 34
0 2 4360 86356 737800 53776 0 0 57436 0 2291 3048 2 19
44 34
0 0 4360 88104 737132 53832 0 0 44675 47 2005 2582 2 15
58 25
But if I try to open another knosole window it freezes...
time dd if=/dev/zero of=/data/testfile bs=1024k count=4096
4096+0 records in
4096+0 records out
real 1m31.687s
user 0m0.024s
sys 0m23.517s
About 44.6MB/s.
No problems with top during the write operation. At least it looses 1sec
every
30 secs.
Cpu used about 25-30% and kswapd about 2%.
If I do a dd on both sda and sdb at the same time:
root@tkamd:/data# time dd if=/dev/sda of=/dev/null bs=1024k count=4096
4096+0 records in
4096+0 records out
real 1m14.899s
user 0m0.033s
sys 0m23.820s
root@tkamd:~# time dd if=/dev/sdb of=/dev/null bs=1024k count=4096
4096+0 records in
4096+0 records out
real 1m15.849s
user 0m0.036s
sys 0m23.419s
So in absolute is good, but in the top session I had a freeze of about 8secs
every 10secs.
vmstat gives in this situation:
procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy
id wa
0 3 12604 211124 629152 46744 0 0 111787 0 3050 4204 2 37
1 61
0 3 12972 96196 743340 46088 0 123 111104 123 3121 4658 3 41
1 56
2 2 12972 96524 743336 46120 0 0 111360 5 3046 4153 1 39
0 60
1 2 12972 96388 743468 46056 0 0 111659 1 3090 4260 3 40
0 57
1 2 12972 96532 743292 46124 0 0 111360 4 2973 3928 3 40
27 31
2 1 12972 96180 743804 46088 0 0 109909 1 3092 4422 3 41
27 30
0 3 12972 95836 744088 46008 0 0 111659 4 2979 3847 1 39
11 49
0 3 12972 95896 744032 45996 0 0 109745 16 3047 4141 3 40
15 42
2 3 12972 96540 743440 45976 0 0 111872 19 3072 4091 1 41
30 28
2 2 12972 96892 743032 46044 0 0 112939 0 3066 4198 0 40
32 28
0 3 12972 96796 743192 46020 0 0 110807 9 3046 3682 1 39
24 36
1 2 12972 96220 743768 45988 0 0 111787 0 3046 3768 1 40
1 58
2 2 12972 96796 743196 46016 0 0 111019 16 3123 3987 2 40
1 58
With parallel write on sda and sdb:
root@tkamd:/data# time dd if=/dev/zero of=/data/testfile bs=1024k count=4096
4096+0 records in
4096+0 records out
real 1m29.197s
user 0m0.034s
sys 0m26.680s
root@tkamd:~# time dd if=/dev/zero of=/mnt/testfile bs=1024k count=4096
4096+0 records in
4096+0 records out
real 1m38.726s
user 0m0.039s
sys 0m28.976s
No problems with top, vmstat or new konsole operations.
Each cpu about 30% loaded and vmstat gives:
procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy
id wa
1 0 12972 491516 328980 61232 0 0 0 51 1173 1556 2 1
97 0
0 0 12972 491384 328980 61232 0 0 0 0 1271 1955 4 2
95 0
1 1 12972 316000 502300 61176 0 0 57797 17 2139 2800 4 20
57 19
4 2 12972 74164 743904 61244 0 0 112696 24 2881 3439 1 38
34 27
1 3 12972 74344 743980 61236 0 0 112256 0 3063 4126 1 41
31 28
0 3 12972 75296 742956 61308 0 0 112597 0 3046 4415 0 41
15 44
1 1 12972 75416 742976 61220 0 0 112469 7 3032 4246 0 40
6 54
1 1 12972 74052 744252 61236 0 0 111445 21 3041 3825 3 41
34 23
1 3 12972 74544 743760 61184 0 0 111232 4 3241 4312 5 43
25 28
1 2 12972 74184 744028 61256 0 0 112981 20 3186 4493 1 42
0 56
procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy
id wa
2 3 12972 74724 743504 61168 0 0 110080 0 3138 4351 6 43
1 51
0 3 12972 74116 744160 61192 0 0 111829 0 3162 4517 1 42
1 56
1 3 12972 74420 743784 61228 0 0 110464 0 3161 4587 2 41
1 56
2 2 12972 75088 743136 61196 0 0 110848 0 3191 4704 3 43
1 53
0 0 12972 483420 336572 61324 0 0 69248 7 2341 3334 3 28
31 37
0 0 12972 483252 336620 61344 0 0 9 0 1120 1373 2 1
96 1
Any hints or I/O operations to be done to give further info on behaviour
are
welcome.
Next days I'm able to do some tests if necessary.
Thanks in advance for your help.
Bye,
Gianluca
>-- Messaggio Originale --
>
>Hello,
>
>Alan wrote> Make sure you enable the SCSI later, SATA drivers and VIA SATA
>driver
>Alan wrote> otherwise you may end up using PIO with the PCI generic IDE
>driver.
>
>Yes, this is up and running, no problem here:
>
>libata version 1.02 loaded.
>sata_via version 0.20
>ACPI: PCI interrupt 0000:00:0f.0[B] -> GSI 20 (level, low) -> IRQ 185
>sata_via(0000:00:0f.0): routed to hard irq line 11
>ata1: SATA max UDMA/133 cmd 0xC000 ctl 0xC402 bmdma 0xD000 irq 185
>ata2: SATA max UDMA/133 cmd 0xC800 ctl 0xCC02 bmdma 0xD008 irq 185
>ata1: dev 0 cfg 49:2f00 82:346b 83:7f21 84:4003 85:3469 86:3c01 87:4003
>88:203f
>ata1: dev 0 ATA, max UDMA/100, 488397168 sectors: lba48
>ata1: dev 0 configured for UDMA/100
>scsi0 : sata_via
>ata2: dev 0 cfg 49:2f00 82:346b 83:7f21 84:4003 85:3469 86:3c01 87:4003
>88:407f
>ata2: dev 0 ATA, max UDMA/133, 72303840 sectors: lba48
>ata2: dev 0 configured for UDMA/133
>scsi1 : sata_via
>Vendor: ATA Model: WDC WD2500JD-00F Rev: 02.0
>Type: Direct-Access ANSI SCSI revision: 05
>Vendor: ATA Model: WDC WD360GD-00FN Rev: 35.0
>Type: Direct-Access ANSI SCSI revision: 05
>SCSI device sda: 488397168 512-byte hdwr sectors (250059 MB)
>SCSI device sda: drive cache: write back
>sda: sda1 sda2
>Attached scsi disk sda at scsi0, channel 0, id 0, lun 0
>SCSI device sdb: 72303840 512-byte hdwr sectors (37020 MB)
>SCSI device sdb: drive cache: write back
>sdb: sdb1
>Attached scsi disk sdb at scsi1, channel 0, id 0, lun 0
>
>
>Tomita, Haruo wrote:
>
> Hi all,
>
>
> VIA/KT800 chipset is not checking.
>
> It seems that it cannot perform in combine mode at the ata_piix driver
>of a version 1.02.
> In this case, although a piix driver should work, ESB_3 is not recognized
>in a piix driver.
> Therefore, it can work only by PIO mode.
>
> Petr, I think that it is necessary to check a setup of BIOS parameters.
> Or how about making this patch reference?
>
> http://marc.theaimsgroup.com/?l=linux-ide&m=109290653905964&w=2
>
> Best regards,
> Haruo
>
>
>Haruo,
>
>I am not using the combine mode on the sata drives (or at least, I don't
>know about it). I was implying that
>when I connect another pure IDE drive to the motherboard, then the situation
>gets better.
>
>Whats wrong here (or ... what feels wrong) is that the system slows down
>noticeably when transferring data
>to/from the sata drives. It 'feels' like using an old ide disk with pio
>mode only. I am not saying that the transfer rates
>are low though... hdparm -t on the sata drives gives me following:
>
>/dev/sda:
>Timing buffered disk reads: 140 MB in 3.01 seconds = 46.46 MB/sec
>
>/dev/sdb:
>Timing buffered disk reads: 164 MB in 3.00 seconds = 54.60 MB/sec
>
>this is not the best, but I think it is acceptable for SATA/PATA drives
>and onboard SATA controller.
>
>It is quite hard to describe what is going wrong here... It might not be
>even related to the sata itself...
>
>One example of the 'slow' system is that when I run 'top -d 1' (top with
>1 second updates), it sometimes
>takes ~4 seconds for the screen to update when the disk io is on action.
>(on dual processor opteron x86_64 machine :-) .Kernel vanilla 2.6.8.
>
>Best Regards,
>Petr
>
>-
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