On Saturday 01 November 2014 02:16:14 Aya Mahfouz wrote: > This patch is concerned with migrating the time variables for the s390 > network driver. The changes handle the y2038 problem where timespec will > overflow in the year 2038. timespec was replaced by unsigned long and > all time variables get their values from the jiffies global variable. > This was done for the sake of speed and efficiency. > > Signed-off-by: Aya Mahfouz <mahfouz.saif.elyazal@xxxxxxxxx> > --- > v1: Arnd has advised me to provide you with options for time > calculation. The first option: "accuracy" is used in this > patch. The second option: "speed" can be done through > jiffies. > > v2: Moved on to the speed option. Let me know if I explicitly > need to include the jiffies header. The module compiles with > no problems on my side. > > v3: Handled the error pointed out by Ursula. The current version > does not handle overflows. There are two solutions for this. > The first is to use jiffies_64 since s/390 is a 64-bit > architecture after all. The second is to use wrapper functions > like time_before and time_after. Two files were added too. > They are: ctcm_main.c and netiucv.c. This patch could be sent > as a patchset in its final version for convenience. Hi Aya, The patch looks correct to me now, Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx> There is one small change that you could do for efficiency: > > - duration = > - (done_stamp.tv_sec - ch->prof.send_stamp.tv_sec) * 1000000 + > - (done_stamp.tv_nsec - ch->prof.send_stamp.tv_nsec) / 1000; > + duration = jiffies_to_usecs(done_stamp - ch->prof.send_stamp); > if (duration > ch->prof.tx_time) > ch->prof.tx_time = duration; > This means you are doing the jiffies_to_usecs conversion for every packet. s390 has a fast multiplication instruction, so it won't matter in practice, but if you do more conversions like this, a better approach is to store the 'jiffies' value in ch->prof.tx_time and only convert it to another unit when printing the number. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
