buffer starvation when recording DVDs

Alexander Best alexbestms at uni-muenster.de
Wed Jul 14 12:20:30 UTC 2010


hi there,

my dvdr drive supports recording DVDs (both DVD-Rs and DVD+Rs) at a
maximum speed of 16x. however at speeds of more than ~12x the burner's
buffer get's filled only ~20%. probably that's why the burner's speed
get's reduced by `growisofs` (to prevent buffer starvation?). how can
this happen? the iso i am using lies on my HDD which is quite fast
(connected via SATA 2.0).

this is the output of `camcontrol devlist -v`:

scbus0 on ahcich0 bus 0:
<>                                 at scbus0 target -1 lun -1 ()
scbus1 on ahcich1 bus 0:
<>                                 at scbus1 target -1 lun -1 ()
scbus2 on ata2 bus 0:
<HL-DT-ST DVDRAM GSA-H10N JL12>    at scbus2 target 0 lun 0 (cd0,pass0)
<>                                 at scbus2 target -1 lun -1 ()
scbus3 on ahcich2 bus 0:
<SAMSUNG SP2504C VT100-50>         at scbus3 target 0 lun 0 (ada0,pass1)
<>                                 at scbus3 target -1 lun -1 ()
scbus4 on ahcich3 bus 0:
<>                                 at scbus4 target -1 lun -1 ()
scbus5 on ahcich4 bus 0:
<>                                 at scbus5 target -1 lun -1 ()
scbus6 on ahcich5 bus 0:
<>                                 at scbus6 target -1 lun -1 ()
scbus7 on ahcich6 bus 0:
<>                                 at scbus7 target -1 lun -1 ()
scbus8 on ahcich7 bus 0:
<>                                 at scbus8 target -1 lun -1 ()
scbus-1 on xpt0 bus 0:
<>                                 at scbus-1 target -1 lun -1 (xpt0)

as you can see cd0 and ada0 don't share the same cable (cd0 is PATA,
ada0 is SATA). the PATA and SATA controllers are:

atapci0: <JMicron JMB363 UDMA133 controller> port
0xd000-0xd007,0xd100-0xd103,0xd200-0xd207,0xd300-0xd303,0xd400-0xd40f
irq 16 at device 0.1 on pci3

ahci0: <JMicron JMB363 AHCI SATA controller> mem 0xf8000000-0xf8001fff
irq 19 at device 0.0 on pci3

this is the output of `growisofs`:

Executing 'builtin_dd if=new.iso of=/dev/pass0 obs=32k seek=0'
/dev/pass0: "Current Write Speed" is 16.4x1352KBps.
          0/4695924736 ( 0.0%) @0x, remaining ??:?? RBU 100.0% UBU   0.0%
          0/4695924736 ( 0.0%) @0x, remaining ??:?? RBU 100.0% UBU   0.0%
          0/4695924736 ( 0.0%) @0x, remaining ??:?? RBU 100.0% UBU   0.0%
          0/4695924736 ( 0.0%) @0x, remaining ??:?? RBU 100.0% UBU   0.0%
          0/4695924736 ( 0.0%) @0x, remaining ??:?? RBU 100.0% UBU   0.0%
          0/4695924736 ( 0.0%) @0x, remaining ??:?? RBU 100.0% UBU   0.0%
          0/4695924736 ( 0.0%) @0x, remaining ??:?? RBU 100.0% UBU   0.0%
    1114112/4695924736 ( 0.0%) @0.2x, remaining 2036:44 RBU 100.0% UBU   2.9%
    1114112/4695924736 ( 0.0%) @0.0x, remaining 2247:26 RBU 100.0% UBU 100.0%
   19365888/4695924736 ( 0.4%) @4.0x, remaining 144:53 RBU 100.0% UBU 100.0%
   52789248/4695924736 ( 1.1%) @7.2x, remaining 57:10 RBU  99.9% UBU 100.0%
   86736896/4695924736 ( 1.8%) @7.4x, remaining 37:11 RBU 100.0% UBU 100.0%
  121241600/4695924736 ( 2.6%) @7.5x, remaining 28:55 RBU 100.0% UBU  97.1%
  156336128/4695924736 ( 3.3%) @7.6x, remaining 23:42 RBU  99.9% UBU  97.1%
  191954944/4695924736 ( 4.1%) @7.7x, remaining 20:20 RBU 100.0% UBU 100.0%
  228130816/4695924736 ( 4.9%) @7.8x, remaining 18:16 RBU 100.0% UBU 100.0%
  264863744/4695924736 ( 5.6%) @8.0x, remaining 16:27 RBU 100.0% UBU 100.0%
  298352640/4695924736 ( 6.4%) @7.3x, remaining 15:13 RBU 100.0% UBU 100.0%
  336134144/4695924736 ( 7.2%) @8.2x, remaining 14:16 RBU 100.0% UBU 100.0%
  374505472/4695924736 ( 8.0%) @8.3x, remaining 13:16 RBU 100.0% UBU 100.0%
  413401088/4695924736 ( 8.8%) @8.4x, remaining 12:25 RBU  99.9% UBU 100.0%
  452886528/4695924736 ( 9.6%) @8.6x, remaining 11:52 RBU 100.0% UBU 100.0%
  492896256/4695924736 (10.5%) @8.7x, remaining 11:13 RBU 100.0% UBU  97.1%
  533495808/4695924736 (11.4%) @8.8x, remaining 10:39 RBU 100.0% UBU  97.1%
  574619648/4695924736 (12.2%) @8.9x, remaining 10:16 RBU  99.7% UBU 100.0%
  616333312/4695924736 (13.1%) @9.0x, remaining 9:49 RBU  99.9% UBU  97.1%
  658538496/4695924736 (14.0%) @9.1x, remaining 9:24 RBU 100.0% UBU  94.1%
  701366272/4695924736 (14.9%) @9.3x, remaining 9:06 RBU 100.0% UBU  97.1%
  744751104/4695924736 (15.9%) @9.4x, remaining 8:45 RBU  99.9% UBU  97.1%
  788660224/4695924736 (16.8%) @9.5x, remaining 8:25 RBU 100.0% UBU  97.1%
  833159168/4695924736 (17.7%) @9.6x, remaining 8:11 RBU 100.0% UBU  97.1%
  878182400/4695924736 (18.7%) @9.8x, remaining 7:53 RBU 100.0% UBU  97.1%
  923762688/4695924736 (19.7%) @9.9x, remaining 7:37 RBU 100.0% UBU  97.1%
  969932800/4695924736 (20.7%) @10.0x, remaining 7:25 RBU 100.0% UBU  97.1%
 1011908608/4695924736 (21.5%) @9.1x, remaining 7:13 RBU 100.0% UBU  97.1%
 1059094528/4695924736 (22.6%) @10.2x, remaining 6:58 RBU 100.0% UBU  97.1%
 1106903040/4695924736 (23.6%) @10.4x, remaining 6:48 RBU 100.0% UBU  97.1%
 1155203072/4695924736 (24.6%) @10.5x, remaining 6:35 RBU 100.0% UBU  97.1%
 1204092928/4695924736 (25.6%) @10.6x, remaining 6:22 RBU  99.9% UBU  97.1%
 1253507072/4695924736 (26.7%) @10.7x, remaining 6:13 RBU 100.0% UBU  97.1%
 1303511040/4695924736 (27.8%) @10.8x, remaining 6:01 RBU 100.0% UBU  97.1%
 1354039296/4695924736 (28.8%) @10.9x, remaining 5:50 RBU 100.0% UBU  97.1%
 1405124608/4695924736 (29.9%) @11.1x, remaining 5:41 RBU 100.0% UBU  91.2%
 1456832512/4695924736 (31.0%) @11.2x, remaining 5:31 RBU  99.9% UBU  97.1%
 1509031936/4695924736 (32.1%) @11.3x, remaining 5:21 RBU 100.0% UBU  97.1%
 1561821184/4695924736 (33.3%) @11.4x, remaining 5:13 RBU  99.9% UBU  97.1%
 1615134720/4695924736 (34.4%) @11.6x, remaining 5:03 RBU 100.0% UBU  91.2%
 1669005312/4695924736 (35.5%) @11.7x, remaining 4:53 RBU 100.0% UBU  97.1%
 1723465728/4695924736 (36.7%) @11.8x, remaining 4:46 RBU 100.0% UBU  91.2%
 1778417664/4695924736 (37.9%) @11.9x, remaining 4:37 RBU 100.0% UBU  97.1%
 1834024960/4695924736 (39.1%) @12.0x, remaining 4:28 RBU  99.5% UBU  97.1%
 1884389376/4695924736 (40.1%) @10.9x, remaining 4:22 RBU 100.0% UBU  47.1%
 1941012480/4695924736 (41.3%) @12.3x, remaining 4:14 RBU  99.9% UBU  97.1%
 1998159872/4695924736 (42.6%) @12.4x, remaining 4:05 RBU 100.0% UBU  97.1%
 2055897088/4695924736 (43.8%) @12.5x, remaining 3:58 RBU  96.6% UBU  94.1%
 2113961984/4695924736 (45.0%) @12.6x, remaining 3:50 RBU 100.0% UBU  82.4%
 2172977152/4695924736 (46.3%) @12.8x, remaining 3:42 RBU 100.0% UBU  79.4%
 2232188928/4695924736 (47.5%) @12.8x, remaining 3:36 RBU 100.0% UBU  79.4%
 2292154368/4695924736 (48.8%) @13.0x, remaining 3:28 RBU 100.0% UBU  73.5%
 2352218112/4695924736 (50.1%) @13.0x, remaining 3:21 RBU  99.9% UBU  41.2%
 2406875136/4695924736 (51.3%) @11.8x, remaining 3:15 RBU 100.0% UBU  23.5%
 2462351360/4695924736 (52.4%) @12.0x, remaining 3:09 RBU 100.0% UBU  20.6%
 2512650240/4695924736 (53.5%) @10.9x, remaining 3:04 RBU 100.0% UBU  20.6%
 2568781824/4695924736 (54.7%) @12.2x, remaining 2:58 RBU  99.8% UBU  20.6%
 2625634304/4695924736 (55.9%) @12.3x, remaining 2:52 RBU  99.9% UBU  20.6%
 2682814464/4695924736 (57.1%) @12.4x, remaining 2:46 RBU 100.0% UBU  20.6%
 2740486144/4695924736 (58.4%) @12.5x, remaining 2:41 RBU  99.9% UBU  20.6%
 2785411072/4695924736 (59.3%) @9.7x, remaining 2:37 RBU  99.5% UBU  20.6%
 2840920064/4695924736 (60.5%) @12.0x, remaining 2:31 RBU 100.0% UBU  97.1%
 2896461824/4695924736 (61.7%) @12.0x, remaining 2:26 RBU 100.0% UBU  94.1%
 2951970816/4695924736 (62.9%) @12.0x, remaining 2:21 RBU 100.0% UBU  97.1%
 3007479808/4695924736 (64.0%) @12.0x, remaining 2:15 RBU  99.9% UBU  97.1%
 3063021568/4695924736 (65.2%) @12.0x, remaining 2:11 RBU  99.8% UBU  88.2%
 3118497792/4695924736 (66.4%) @12.0x, remaining 2:05 RBU 100.0% UBU  97.1%
 3174039552/4695924736 (67.6%) @12.0x, remaining 2:00 RBU 100.0% UBU  97.1%
 3229581312/4695924736 (68.8%) @12.0x, remaining 1:56 RBU  99.9% UBU  97.1%
 3285090304/4695924736 (70.0%) @12.0x, remaining 1:51 RBU 100.0% UBU  97.1%
 3340599296/4695924736 (71.1%) @12.0x, remaining 1:46 RBU 100.0% UBU  97.1%
 3396141056/4695924736 (72.3%) @12.0x, remaining 1:41 RBU  99.9% UBU  97.1%
 3451682816/4695924736 (73.5%) @12.0x, remaining 1:36 RBU  99.9% UBU  97.1%
 3507191808/4695924736 (74.7%) @12.0x, remaining 1:32 RBU 100.0% UBU  94.1%
 3562733568/4695924736 (75.9%) @12.0x, remaining 1:27 RBU 100.0% UBU  91.2%
 3618242560/4695924736 (77.1%) @12.0x, remaining 1:23 RBU 100.0% UBU  91.2%
 3673784320/4695924736 (78.2%) @12.0x, remaining 1:18 RBU 100.0% UBU  94.1%
 3729293312/4695924736 (79.4%) @12.0x, remaining 1:14 RBU 100.0% UBU  94.1%
 3784835072/4695924736 (80.6%) @12.0x, remaining 1:09 RBU 100.0% UBU  94.1%
 3840344064/4695924736 (81.8%) @12.0x, remaining 1:05 RBU 100.0% UBU  97.1%
 3895885824/4695924736 (83.0%) @12.0x, remaining 1:00 RBU 100.0% UBU  70.6%
 3951427584/4695924736 (84.1%) @12.0x, remaining 0:56 RBU 100.0% UBU  97.1%
 4006936576/4695924736 (85.3%) @12.0x, remaining 0:51 RBU 100.0% UBU  97.1%
 4062478336/4695924736 (86.5%) @12.0x, remaining 0:47 RBU 100.0% UBU  97.1%
 4118020096/4695924736 (87.7%) @12.0x, remaining 0:43 RBU 100.0% UBU  97.1%
 4173529088/4695924736 (88.9%) @12.0x, remaining 0:39 RBU 100.0% UBU  97.1%
 4229103616/4695924736 (90.1%) @12.0x, remaining 0:34 RBU 100.0% UBU  97.1%
 4284579840/4695924736 (91.2%) @12.0x, remaining 0:30 RBU 100.0% UBU  97.1%
 4340154368/4695924736 (92.4%) @12.0x, remaining 0:26 RBU 100.0% UBU  97.1%
 4395663360/4695924736 (93.6%) @12.0x, remaining 0:22 RBU 100.0% UBU  97.1%
 4451237888/4695924736 (94.8%) @12.0x, remaining 0:18 RBU  99.9% UBU  97.1%
 4506779648/4695924736 (96.0%) @12.0x, remaining 0:13 RBU  99.9% UBU  97.1%
 4562321408/4695924736 (97.2%) @12.0x, remaining 0:09 RBU  99.9% UBU  97.1%
 4617830400/4695924736 (98.3%) @12.0x, remaining 0:05 RBU 100.0% UBU  97.1%
 4673372160/4695924736 (99.5%) @12.0x, remaining 0:01 RBU  67.3% UBU  97.1%
builtin_dd: 2292944*2KB out @ average 9.9x1352KBps
/dev/pass0: flushing cache
/dev/pass0: closing track
/dev/pass0: closing disc

i also noticed this output (console):

(cd0:ata2:0:0:0): READ TOC/PMA/ATIP. CDB: 43 0 0 0 0 0 0 0 4 0
(cd0:ata2:0:0:0): CAM status: SCSI Status Error
(cd0:ata2:0:0:0): SCSI status: Check Condition
(cd0:ata2:0:0:0): SCSI sense: ILLEGAL REQUEST csi:43,0,0,e asc:24,0
(Invalid field in CDB): Command byte 6 is invalid
(cd0:ata2:0:0:0): READ TOC/PMA/ATIP. CDB: 43 0 0 0 0 0 0 0 4 0
(cd0:ata2:0:0:0): CAM status: SCSI Status Error
(cd0:ata2:0:0:0): SCSI status: Check Condition
(cd0:ata2:0:0:0): SCSI sense: ILLEGAL REQUEST csi:43,0,0,e asc:24,0
(Invalid field in CDB): Command byte 6 is invalid

my motherboard features a second SATA controller:

ahci1: <Intel ICH9 AHCI SATA controller> port
0xe600-0xe607,0xe700-0xe703,0xe800-0xe807,0xe900-0xe903,0xea00-0xea1f
mem 0xf8206000-0xf82067ff irq 19 at device 31.2 on pci0

should i consider moving my hdd to this controller? i heard the
jmicron controllers don't work very well under freebsd.

i'm running

FreeBSD otaku 9.0-CURRENT FreeBSD 9.0-CURRENT #4 r209884: Sat Jul 10
19:25:16 CEST 2010     root at otaku:/usr/obj/usr/src/sys/ARUNDEL  amd64

with

options		ATA_CAM

in my kernel config.

cheers.

ps: during the `growisofs` session i made sure that no other
application was causing heavy HDD activity!!!


-- 
Alexander Best


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