+Cc John Gary (who is working on the PPTT with me) Hi Jeffrey, On 2017/8/8 1:10, Jeffrey Hugo wrote: > On 8/7/2017 4:20 AM, Hanjun Guo wrote: >> +Cc Xiongfeng (who is also working on the PPTT but focusing on >> CPU topology) >> >> Hi Jeremy, >> >> On 2017/8/5 8:11, Jeremy Linton wrote: >>> ACPI 6.2 adds the Processor Properties Topology Table (PPTT), which is >>> used to describe the processor and cache topologies. Ideally it is >>> used to extend/override information provided by the hardware, but >>> right now ARM64 is entirely dependent on firmware provided tables. >>> >>> This patch parses the table for the cache topology only. Its quite >>> trivial to add processor/cluster/???/socket level parsing as well, >>> but that information isn't as useful as the already provided NUMA >>> SRAT/SLIT information which provides relative distances. The one >>> useful thing, is the number of physical sockets but due to the >>> way arm64 considers "clusters" to be sockets, a larger discussion >>> is required here. >> >> I think we need the socket to represent the true topology of >> the SoC, which means that considering clusters to be sockets is >> wrong on ARM64 server platforms, a "socket" needs to be a memory >> controller attached I think. >> >> Take D05 for example, there are two physical SoC sockets on >> the board but with two CPU DIE (with memory controller) on each >> physical socket, and 4 clusters on each CPU DIE. >> >> When considering clusters as sockets (that's the code for now), >> there are 16 "sockets" to represent to OS for schedule input, >> but only 4 NUMA nodes, which are confusing the scheduler a lot... >> >> Xiongfeng was working on the CPU topology based on PPTT, and the code >> is under internal review, if it's OK for you, we can send them out >> for review comments to see if we can join our effort together, or >> we can work on top of your patches, as you like :) >> >>> >>> An example of lstopo with this patch: >>> >>> [root@mammon-juno-rh ~]# lstopo-no-graphics >>> Machine (8072MB) >>> Package L#0 + L2 L#0 (1024KB) >>> L1d L#0 (32KB) + L1i L#0 (32KB) + Core L#0 + PU L#0 (P#0) >>> L1d L#1 (32KB) + L1i L#1 (32KB) + Core L#1 + PU L#1 (P#1) >>> L1d L#2 (32KB) + L1i L#2 (32KB) + Core L#2 + PU L#2 (P#2) >>> L1d L#3 (32KB) + L1i L#3 (32KB) + Core L#3 + PU L#3 (P#3) >>> Package L#1 + L2 L#1 (2048KB) >>> L1d L#4 (32KB) + L1i L#4 (48KB) + Core L#4 + PU L#4 (P#4) >>> L1d L#5 (32KB) + L1i L#5 (48KB) + Core L#5 + PU L#5 (P#5) >>> HostBridge L#0 >>> PCIBridge >>> PCIBridge >>> PCIBridge >>> PCI 1095:3132 >>> Block(Disk) L#0 "sda" >>> PCIBridge >>> PCI 11ab:4380 >>> Net L#1 "enp8s0" >>> >>> Jeremy Linton (4): >>> drivers: base: cacheinfo: Add support for ACPI based firmware tables >>> arm64: cacheinfo: Add support for ACPI/PPTT generated topology >>> ACPI/PPTT: Add Processor Properties Topology Table parsing >>> ACPI: Enable PPTT support on ARM64 >>> >>> arch/arm64/kernel/cacheinfo.c | 23 ++- >>> drivers/acpi/arm64/Kconfig | 3 + >>> drivers/acpi/arm64/Makefile | 1 + >>> drivers/acpi/arm64/pptt.c | 389 ++++++++++++++++++++++++++++++++++++++++++ >> >> I think PPTT is not ARM64 only, can be used for x86 too, >> shall we locate them on drivers/acpi? > > Austin and I have been working on the CPU topology. Sounds like we have some overlap with your work. We have a working prototype at https://source.codeaurora.org/quic/server/kernel/log/?h=jhugo/pptt but are still doing some cleanup and fixes for our needs. > > Drivers/acpi makes sense to us, and was our working assumption. > John and I have also been working on the CPU topology. Our code can be got at https://github.com/fenghusthu/acpi_pptt . I have tested it on the D05 board and it is OK. Maybe we can work together, combine our codes, and make a better code structure. >> >> Rafael was working a lot on the PPTT proposal for the >> spec, I think he can comment on this :) >> >> Rafael, what do you think? >> >> Thanks >> Hanjun >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
