On Tue, 28 Mar 2017 19:05:12 +0300 Tariq Toukan <ttoukan.linux@xxxxxxxxx> wrote: > On 28/03/2017 10:32 AM, Tariq Toukan wrote: > > > > > > On 27/03/2017 4:32 PM, Mel Gorman wrote: > >> On Mon, Mar 27, 2017 at 02:39:47PM +0200, Jesper Dangaard Brouer wrote: > >>> On Mon, 27 Mar 2017 10:55:14 +0200 > >>> Jesper Dangaard Brouer <brouer@xxxxxxxxxx> wrote: > >>> > >>>> A possible solution, would be use the local_bh_{disable,enable} instead > >>>> of the {preempt_disable,enable} calls. But it is slower, using numbers > >>>> from [1] (19 vs 11 cycles), thus the expected cycles saving is > >>>> 38-19=19. > >>>> > >>>> The problematic part of using local_bh_enable is that this adds a > >>>> softirq/bottom-halves rescheduling point (as it checks for pending > >>>> BHs). Thus, this might affects real workloads. > >>> > >>> I implemented this solution in patch below... and tested it on mlx5 at > >>> 50G with manually disabled driver-page-recycling. It works for me. > >>> > >>> To Mel, that do you prefer... a partial-revert or something like this? > >>> > >> > >> If Tariq confirms it works for him as well, this looks far safer patch > > > > Great. > > I will test Jesper's patch today in the afternoon. > > > > It looks very good! > I get line-rate (94Gbits/sec) with 8 streams, in comparison to less than > 55Gbits/sec before. Just confirming, this is when you have disabled mlx5 driver page-recycling, right? > >> than having a dedicate IRQ-safe queue. Your concern about the BH > >> scheduling point is valid but if it's proven to be a problem, there is > >> still the option of a partial revert. -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>