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This commit introduces BPF ASM helpers for MIPS and MIPS64 kernels. The purpose of this patch is to twofold: 1) We are now able to handle negative offsets instead of either falling back to the interpreter or to simply not do anything and bail out. 2) Optimize reads from the packet header instead of calling the C helpers Because of this patch, we are now able to get rid of quite a bit of code in the JIT generation process by using MIPS optimized assembly code. The new assembly code makes the test_bpf testsuite happy with all 60 test passing successfully compared to the previous implementation where 2 tests were failing. Doing some basic analysis in the results between the old implementation and the new one we can obtain the following summary running current mainline on an ER8 board (+/- 30us delta is ignored to prevent noise from kernel scheduling or IRQ latencies): Summary: 22 tests are faster, 7 are slower and 47 saw no improvement with the most notable improvement being the tcpdump tests. The 7 tests that seem to be a bit slower is because they all follow the slow path (bpf_internal_load_pointer_neg_helper) which is meant to be slow so that's not a problem. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: netdev@vger.kernel.org Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: netdev@vger.kernel.org Patchwork: http://patchwork.linux-mips.org/patch/10530/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> |
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| bpf_jit_asm.S | ||
| bpf_jit.c | ||
| bpf_jit.h | ||
| Makefile | ||