Messages in this thread | | | Subject | Re: Huge iowait on 2.6.4 - not on 2.4.20 ! | From | Albert Cahalan <> | Date | 16 Apr 2004 11:12:47 -0400 |
| |
alan pearson writes:
> On 2.6 the iowait jumps to around 70%, while 2.4 on > both tests it is firmly zero.
The 2.4 kernel lumps iowait into idle, so you won't see iowait on a 2.4 kernel.
> On disk read, I'm loosing 30 Mb/sec of bandwidth PER > DISK, compared to 2.4.20. > I've tried using both the deadline and as ioschedulers > but no difference. > > > Under real conditions (ie our application running > which reads from all the disks simultaneously) on > 2.6.4, the system performance is around 1/3 of 2.4.20) > > Summary MB/Sec : > > dd if=x dd if=/dev/zero > 2.4 64 35.6 > 2.6 30.34 35.9
Well, that looks serious, but unfortunately you can't tell what the iowait was on the 2.4 kernel. Only the 2.6 kernel provides this information.
- 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/
| |