On Tue, Jun 14, 2016 at 06:54:22PM -0300, Guilherme G. Piccoli wrote: > On 06/14/2016 04:58 PM, Christoph Hellwig wrote: >> This is lifted from the blk-mq code and adopted to use the affinity mask >> concept just intruced in the irq handling code. > > Very nice patch Christoph, thanks. There's a little typo above, on > "intruced". fixed. > Another little typo above in "assining". fixed a swell. > I take this opportunity to ask you something, since I'm working in a > related code in a specific driver Which driver? One of the points here is to get this sort of code out of drivers and into common code.. > - sorry in advance if my question is > silly or if I misunderstood your code. > > The function irq_create_affinity_mask() below deals with the case in which > we have nr_vecs < num_online_cpus(); in this case, wouldn't be a good idea > to trying distribute the vecs among cores? > > Example: if we have 128 online cpus, 8 per core (meaning 16 cores) and 64 > vecs, I guess would be ideal to distribute 4 vecs _per core_, leaving 4 > CPUs in each core without vecs. There have been some reports about the blk-mq IRQ distribution being suboptimal, but no one sent patches so far. This patch just moves the existing algorithm into the core code to be better bisectable. I think an algorithm that takes cores into account instead of just SMT sibling would be very useful. So if you have a case where this helps for you an incremental patch (or even one against the current blk-mq code for now) would be appreciated. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
