On Wed, 24 Sep 2014 09:04:44 -0400 Tejun Heo <tj@xxxxxxxxxx> wrote: > Hello, Alexander. > > On Wed, Sep 24, 2014 at 11:42:15AM +0100, Alexander Gordeev wrote: > > On Tue, Sep 23, 2014 at 04:57:10PM -0400, Tejun Heo wrote: > > > Hmmm... how does it affect single device operation tho? It does make > > > individual interrupt handling heavier, no? > > > > I think it is difficult to assess "individual interrupt handling", since > > it depends from both the hardware and device access pattern. On the system > > I use the results are rather counter-intuitive: ahci_thread_fn() does not > > show up in perf report at all, nor ahci_single_irq_intr(). While before > > the change ahci_single_irq_intr() reported 0.00%. > > > > But since the handling is split in two parts it is rather incorrect to > > apply the same metric to the threaded context. Obviously, the threaded > > handler is expected slowed down by other interrupts handlers, but the > > whole system should benefit from it, which is exactly the aim of this > > change. > > Hmmm, how would the whole system benefit from it if there's only > single device? Each individual servicing of the interrupt does more > now which includes scheduling which may end up adding to completion > latency. > I think he meant other, non-AHCI, interrupt handlers would benefit. A good test of this patch might be to stream 10Gb ethernet while also streaming writes to an AHCI device. -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
