On Fri, 20 Dec 2002, at 11:17am, [EMAIL PROTECTED] wrote: > Without all of that information, unless you can show that the system's I/O > requests exceeded the system's capacity to provide I/O during some time > period ...
But is Paul really looking for that kind of detail? It sounds to me like Paul just wants to know how much time the *system* spends waiting for the disk (or disks). Compare that to total system time, and you have a fair indication of whether the system is waiting on the disk a lot. Maybe the system isn't waiting on the disk a lot, in which case, you look elsewhere for the cause of your performance problem. (Paul, if I'm wrong in my assumptions about what you want, please say so.) You could measure time spent waiting on the disk in the device driver fairly easily. First, the driver would have to note the time a request is submitted to the disk. Then, when the result comes back, the driver would note the new time, take the difference, and add the difference to some counter somewhere. Of course, I have no idea if Linux, or any of the disk device drivers, actually *do* this, but I wouldn't think it would be *that* hard. Of course, I really don't have any idea what I am talking about, but that's never stopped me before.... ;-) -- Ben Scott <[EMAIL PROTECTED]> | The opinions expressed in this message are those of the author and do not | | necessarily represent the views or policy of any other person, entity or | | organization. All information is provided without warranty of any kind. | _______________________________________________ gnhlug-discuss mailing list [EMAIL PROTECTED] http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss
