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I have encountered several systems that have an invalid tag map. This invalid tag map results in only two tags being generated 0x1F which is usually applied to the first core in a Hyper-threaded pair and 0x00 which is applied to the second core in a Hyper-threaded pair. The net result of all this is that DCA causes significant cache thrash because the 0x1F tag will send traffic to the second socket, which the 0x00 tag will not DCA tag the frame resulting in no benefit. For now the best solution from the driver's perspective is to just disable DCA if the tag map is invalid. The correct solution for this would be to have the BIOS on affected systems updated so that the correct tags are generated for a given APIC ID. Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> Tested-by: Stephen Ko <stephen.s.ko@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> |
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| .. | ||
| dca.c | ||
| dma_v2.c | ||
| dma_v2.h | ||
| dma_v3.c | ||
| dma.c | ||
| dma.h | ||
| hw.h | ||
| Makefile | ||
| pci.c | ||
| registers.h | ||