On 10/14/19 8:28 PM, Hou Tao wrote: > For network stack, RPS, namely Receive Packet Steering, is used to > distribute network protocol processing from hardware-interrupted CPU > to specific CPUs and alleviating soft-irq load of the interrupted CPU. > > For block layer, soft-irq (for single queue device) or hard-irq > (for multiple queue device) is used to handle IO completion, so > RPS will be useful when the soft-irq load or the hard-irq load > of a specific CPU is too high, or a specific CPU set is required > to handle IO completion. > > Instead of setting the CPU set used for handling IO completion > through sysfs or procfs, we can attach an eBPF program to the > request-queue, provide some useful info (e.g., the CPU > which submits the request) to the program, and let the program > decides the proper CPU for IO completion handling. > But it looks like there isn't any benefit than through sysfs/procfs? > In order to demonostrate the effect of IO completion redirection, > a test programm is built to redirect the IO completion handling > to all online CPUs or a specific CPU set: > > ./test_blkdev_ccpu -d /dev/vda > or > ./test_blkdev_ccpu -d /dev/nvme0n1 -s 4,8,10-13 > > However I am still trying to find out a killer scenario for Speaking about scenario, perhaps attaching a filter could be useful? So that the data can be processed the first place. - Bob > the eBPF redirection, so suggestions and comments are welcome. > > Regards, > Tao > > Hou Tao (2): > block: add support for redirecting IO completion through eBPF > selftests/bpf: add test program for redirecting IO completion CPU > > block/Makefile | 2 +- > block/blk-bpf.c | 127 +++++++++ > block/blk-mq.c | 22 +- > block/blk-softirq.c | 27 +- > include/linux/blkdev.h | 3 + > include/linux/bpf_blkdev.h | 9 + > include/linux/bpf_types.h | 1 + > include/uapi/linux/bpf.h | 2 + > kernel/bpf/syscall.c | 9 + > tools/include/uapi/linux/bpf.h | 2 + > tools/lib/bpf/libbpf.c | 1 + > tools/lib/bpf/libbpf_probes.c | 1 + > tools/testing/selftests/bpf/Makefile | 1 + > .../selftests/bpf/progs/blkdev_ccpu_rr.c | 66 +++++ > .../testing/selftests/bpf/test_blkdev_ccpu.c | 246 ++++++++++++++++++ > 15 files changed, 507 insertions(+), 12 deletions(-) > create mode 100644 block/blk-bpf.c > create mode 100644 include/linux/bpf_blkdev.h > create mode 100644 tools/testing/selftests/bpf/progs/blkdev_ccpu_rr.c > create mode 100644 tools/testing/selftests/bpf/test_blkdev_ccpu.c >
