Messages in this thread | | | Subject | Re: I/O issues, iowait problems, 2.4 v 2.6 | From | Paul Venezia <> | Date | 10 Nov 2003 23:02:08 -0500 |
| |
On Mon, 2003-11-10 at 22:54, Andrew Morton wrote: > Eventually, the bottleneck disappears, > > and the performance increases, but never substantially. > > It's not clear here what direction the data is being transferred in. Is it > mostly client->server, or mostly server->client?
Seems to be bidirectional.
> What filesystem is the server using?
ext3
> In which direction was the file transferred? client to server or server to > client? What kernel was running on each?
The client is running AS2.1, RH's 2.4.9-e12. Server is RH AS 3.0, 2.4.22 stock, and 2.6.0-test9, 2.6.0-test9-bk11. Transfers in both directions. > > As next steps I'd suggest that you log into the server and do > > time (dd if=/dev/zero of=x bs=1M count=2048 ; sync) > > and > > time (dd if=x of=/dev/null bs=1M count=2048 ; sync) > > (this assumes that the machine has less that 2G of memory, to avoid caching > effects).
The raw file read/write is the ticket. The box tightens right up at 100% iowait.
I'd done bonnie++ i/o tests already, and except for an apparent NPTL issue on the per char, the block i/o numbers were fine; no abnormal results whatsoever. In fact, block r/w numbers were improved compared to 2.4.22. Now that I'm looking for it, however, I do note extremely elevated iowait numbers during a bonnie++ run. Something in the MPT modules?
-Paul
- 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/
| |