On Sat, Dec 17, 2011 at 5:03 PM, Or Gerlitz <[email protected]> wrote: > Bart Van Assche <[email protected]> wrote: > >> The default block layer timeout is 30 seconds. > > Could you provider a pointer to where this is defined?
Sorry, it's not the block layer but sd (SCSI disk) that sets that timeout value. From drivers/scsi/sd.h: #define SD_TIMEOUT (30 * HZ) >> Typical values for the QP local ack >> timeout and retry count are 19 and 7 respectively, which means >> that it can take up to 60.1 seconds before a HCA submits an error completion. > > isn't timeout(R,X) = R * ~4us * 2^X ==> timeout(7,19) = 7 * ~2seconds > = ~14 seconds I started looking at the timeout settings after I noticed while performing cable pulling tests with an mlx4-controlled HCA that it could take up to (about) 61 seconds before an error completion was delivered. And it looks like Dave already answered the question where the factor four comes from ? Bart. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
