Messages in this thread | | | Date | Thu, 7 Nov 2002 20:53:16 -0500 | From | Adam Kropelin <> | Subject | Re: 2.5.46: ide-cd cdrecord success report |
| |
On Thu, Nov 07, 2002 at 08:14:09PM +0200, MdkDev wrote: > > > Thanks, this is good information. Was the destination for the 'dd' and > > the source CD image on the same drive? What filesystem were you using? > > Yes, destination for the dd and the source for the CD image was on the > same drive. I'm using ext3 filesystem. > > > I notice you used a 4x writer...I'll try lowering my write speed to 4x > > and see if that makes a difference. I'll also see if I can rig up an > > IDE disk instead of SCSI. > > The burner is capable of writing 16x (CDR) or 10x (CDRW) but the speed was > 4x in this case because of the media. I'll try and repeat the test using > max speed.
I've done some more testing and narrowed the problem down a little. I switched to an IDE drive to rule out SCSI and found that the problem is still with me: a parallel `dd` to the image source drive still kills burn.
Then I lowered the write speed from 12x down to 4x to match yours...and then the problem went away. A look at `vmstat 1` shows that the heavy write load causes the read throughput to drop to about 768 KB/sec. That's far too slow for 12x but is just about right for 4x. Makes sense, then that a 4x burn survives.
It's easy to duplicate without involving cdrecord at all. Just do...
dd if=/dev/hda1 of=/dev/null bs=1M
...in parallel with...
dd if=/dev/zero of=/mnt/foo bs=1M
When you kick in the write load, the read throughput drops to < 1 MB/sec. `vmstat 1` output below shows the transition...
--Adam
procs memory swap io system cpu r b w swpd free buff cache si so bi bo in cs us sy id 2 0 0 4272 112684 20356 36856 0 0 0 16 1016 72 5 0 95 0 1 1 4272 108476 23676 36856 0 0 3320 0 1067 224 13 4 83 1 0 1 4272 96656 35580 36856 0 0 11904 0 1192 474 30 39 30 0 1 0 4272 84836 47356 36856 0 0 11776 0 1192 463 30 42 27 0 1 1 4272 72956 59268 36856 0 0 11904 40 1313 1139 44 38 18 0 1 0 4272 61076 71044 36856 0 0 11776 0 1200 478 29 43 29 0 1 0 4272 49256 82828 36856 0 0 11784 0 1199 522 39 37 24 0 1 0 4272 37196 94732 36856 0 0 11904 0 1199 497 35 38 26 0 1 0 4272 25256 106508 36856 0 0 11776 0 1199 512 32 43 24 1 2 3 4692 2468 75604 90132 0 420 9608 10888 1189 721 19 75 6 0 2 3 4692 3540 46932 117580 0 0 808 10428 1093 287 30 70 0 0 2 3 4692 3448 42916 121624 0 0 1024 8824 1099 266 65 35 0 0 2 3 4692 3200 35152 129692 0 0 1024 6512 1088 294 55 45 0 0 2 4 4692 1564 24640 141696 0 0 768 7688 1091 277 44 56 0 1 1 2 4692 3492 19044 145484 0 0 1024 5956 1084 285 69 31 0 0 2 3 4692 3492 12020 152448 0 0 768 7192 1085 298 55 45 0 0 2 3 4692 3432 12444 152056 0 0 676 6852 1086 266 55 45 0 0 2 3 4692 3612 12196 152288 0 0 768 5724 1083 287 55 45 0 0 2 3 4692 3552 12580 151900 0 0 768 7756 1088 272 65 35 0 2 2 3 4692 3492 12840 152048 0 0 1024 5032 1195 691 66 34 0 0 2 3 4692 3792 13304 151212 0 0 772 7452 1191 586 60 40 0
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |