Hi! Wouldn't it be more obvious to calculate the average delay to a ping request? (Possibly exponential average as for the system loads) (min and Max would be good as well, but standard deviation probably requires use of the FPU, so that's not possible in kernel modules (AFAIK)).
Regards, Ulrich On 18 Nov 2009 at 18:29, Erez Zilber wrote: > open-iscsi sends nop-outs to the target. If the target responds quick > enough, we don't get a timeout. I'd like to know (for internal debug > purposes) how many times the ping timer almost expired. This sounds > like a useful feature also for other open-iscsi developers/users. > > I was thinking about adding the following mechanism: > > 1. Add an array of some length to store long nop-outs. Protect it with > some lock. > 2. If a nop-in (as a response to nop-out) was received after >= 0.7 * > ping_to (or 0.8 or whatever), add some info about it to the array > (when was the nop-out sent, how much time until we got a nop-in etc). > 3. The array should be used in a cyclic way - when it gets full, > overwrite the 1st entry. > 4. We can dump the info from the array from time to time or the user > may use iscsiadm to do that. When this is done, we can delete the > contents of the array. > > Comments? Objections? > > Erez > > -- > > You received this message because you are subscribed to the Google Groups > "open-iscsi" group. > To post to this group, send email to open-is...@googlegroups.com. > To unsubscribe from this group, send email to > open-iscsi+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/open-iscsi?hl=. > > -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To post to this group, send email to open-is...@googlegroups.com. To unsubscribe from this group, send email to open-iscsi+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/open-iscsi?hl=.
