Ah, so it's just the representation that's confusing! 352: 2 3 4 5 6 7 8 9 360: 10 11 12 13 0 1 2 3
Core 9 corresponds to 359 indeed. Thanks for the explanation, I can see why. On Wed, Nov 22, 2017 at 6:39 PM, Michał Purzyński < michalpurzyns...@gmail.com> wrote: > Thanks, it's almost clear now - one more thing. There seems to be 8 > columns in this table. Let's say the lowest 9 bits of my hash are 8 decimal > > For 8 the table reads > > 8: 8 9 10 11 12 13 0 1 > > The value 8 is an index into a table that yields a row - which of those > cores would be used? The packet could you go a core 8 or 9 or 12? > > > On Wed, Nov 22, 2017 at 5:55 PM, Alexander Duyck < > alexander.du...@gmail.com> wrote: > >> Comments inline below. >> >> On Wed, Nov 22, 2017 at 8:23 AM, Michał Purzyński >> <michalpurzyns...@gmail.com> wrote: >> > Hello! >> > >> > How do I read the indirection table, then one that can be shown with >> > ethtool -x? What is the meaning of columns vs rows and what those >> numbers >> > are trying to tell me? I'm guessing it's kind of like a weight, but I'm >> not >> > sure how to understand it. >> >> So what the indirection table does is allow us to map bits from the >> RSS hash onto specific rings. >> >> So in the example you provided below there are 512 entries, this >> represents 9 bits. Those 9 bits appear to be mapped onto 14 queues >> based on the table you provided. >> >> So the easiest way to examine this would be to look at skb->hash that >> is being reported by the device in the case of flow director/ATR being >> disabled. What you should find is that if you mask the skb->hash by >> masking it with 511 (0x1FF) what you should find is that the number >> returned will give you the index into this table, and the packet >> itself should be received on the queue associated with that index. >> >> > RX flow hash indirection table for p3p1 with 14 RX ring(s): >> > >> > 0: 0 1 2 3 4 5 6 7 >> > 8: 8 9 10 11 12 13 0 1 >> > 16: 2 3 4 5 6 7 8 9 >> > 24: 10 11 12 13 0 1 2 3 >> > 32: 4 5 6 7 8 9 10 11 >> > 40: 12 13 0 1 2 3 4 5 >> > 48: 6 7 8 9 10 11 12 13 >> > 56: 0 1 2 3 4 5 6 7 >> > 64: 8 9 10 11 12 13 0 1 >> > 72: 2 3 4 5 6 7 8 9 >> > 80: 10 11 12 13 0 1 2 3 >> > 88: 4 5 6 7 8 9 10 11 >> > 96: 12 13 0 1 2 3 4 5 >> > 104: 6 7 8 9 10 11 12 13 >> > 112: 0 1 2 3 4 5 6 7 >> > 120: 8 9 10 11 12 13 0 1 >> > 128: 2 3 4 5 6 7 8 9 >> > 136: 10 11 12 13 0 1 2 3 >> > 144: 4 5 6 7 8 9 10 11 >> > 152: 12 13 0 1 2 3 4 5 >> > 160: 6 7 8 9 10 11 12 13 >> > 168: 0 1 2 3 4 5 6 7 >> > 176: 8 9 10 11 12 13 0 1 >> > 184: 2 3 4 5 6 7 8 9 >> > 192: 10 11 12 13 0 1 2 3 >> > 200: 4 5 6 7 8 9 10 11 >> > 208: 12 13 0 1 2 3 4 5 >> > 216: 6 7 8 9 10 11 12 13 >> > 224: 0 1 2 3 4 5 6 7 >> > 232: 8 9 10 11 12 13 0 1 >> > 240: 2 3 4 5 6 7 8 9 >> > 248: 10 11 12 13 0 1 2 3 >> > 256: 4 5 6 7 8 9 10 11 >> > 264: 12 13 0 1 2 3 4 5 >> > 272: 6 7 8 9 10 11 12 13 >> > 280: 0 1 2 3 4 5 6 7 >> > 288: 8 9 10 11 12 13 0 1 >> > 296: 2 3 4 5 6 7 8 9 >> > 304: 10 11 12 13 0 1 2 3 >> > 312: 4 5 6 7 8 9 10 11 >> > 320: 12 13 0 1 2 3 4 5 >> > 328: 6 7 8 9 10 11 12 13 >> > 336: 0 1 2 3 4 5 6 7 >> > 344: 8 9 10 11 12 13 0 1 >> > 352: 2 3 4 5 6 7 8 9 >> > 360: 10 11 12 13 0 1 2 3 >> > 368: 4 5 6 7 8 9 10 11 >> > 376: 12 13 0 1 2 3 4 5 >> > 384: 6 7 8 9 10 11 12 13 >> > 392: 0 1 2 3 4 5 6 7 >> > 400: 8 9 10 11 12 13 0 1 >> > 408: 2 3 4 5 6 7 8 9 >> > 416: 10 11 12 13 0 1 2 3 >> > 424: 4 5 6 7 8 9 10 11 >> > 432: 12 13 0 1 2 3 4 5 >> > 440: 6 7 8 9 10 11 12 13 >> > 448: 0 1 2 3 4 5 6 7 >> > 456: 8 9 10 11 12 13 0 1 >> > 464: 2 3 4 5 6 7 8 9 >> > 472: 10 11 12 13 0 1 2 3 >> > 480: 4 5 6 7 8 9 10 11 >> > 488: 12 13 0 1 2 3 4 5 >> > 496: 6 7 8 9 10 11 12 13 >> > 504: 0 1 2 3 4 5 6 7 >> >> So for example if I had an RSS hash that was something like 0x01234567 >> and I masked the lower 9 bits I would get 0x167, which comes out as >> 359 decimal. As such I would expect the packet to be received on queue >> 9 based on the table provided here. >> >> I hope that helps to clarify how the indirection table is used. >> >> - Alex >> > > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
