Yeah, I think you get it. The 8 columns is just the layout of how they decided to print the table. They are printing 8 entries per row.
- Alex On Wed, Nov 22, 2017 at 9:43 AM, Michał Purzyński <michalpurzyns...@gmail.com> wrote: > 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
