diff options
author | Jakub Kicinski <jakub.kicinski@netronome.com> | 2017-10-23 11:58:14 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2017-10-24 17:38:37 +0900 |
commit | 9f16c8abcd79fc31a74d3af64f085a009c9d4b5a (patch) | |
tree | d022dc299e72425908879b4373be6fde515f471f /drivers/net/ethernet/netronome | |
parent | b14157eeed4eff2b293e0ca7738f6a3dbfff51cc (diff) | |
download | linux-9f16c8abcd79fc31a74d3af64f085a009c9d4b5a.tar.bz2 |
nfp: bpf: optimize mov64 a little
Loading 64bit constants require up to 4 load immediates, since
we can only load 16 bits at a time. If the 32bit halves of
the 64bit constant are the same, however, we can save a cycle
by doing a register move instead of two loads of 16 bits.
Note that we don't optimize the normal ALU64 load because even
though it's a 64 bit load the upper half of the register is
a coming from sign extension so we can load it in one cycle
anyway.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/netronome')
-rw-r--r-- | drivers/net/ethernet/netronome/nfp/bpf/jit.c | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/jit.c b/drivers/net/ethernet/netronome/nfp/bpf/jit.c index d84f00b80aac..e7eeb7a07f81 100644 --- a/drivers/net/ethernet/netronome/nfp/bpf/jit.c +++ b/drivers/net/ethernet/netronome/nfp/bpf/jit.c @@ -1384,19 +1384,28 @@ static int end_reg32(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) static int imm_ld8_part2(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) { - wrp_immed(nfp_prog, reg_both(nfp_meta_prev(meta)->insn.dst_reg * 2 + 1), - meta->insn.imm); + struct nfp_insn_meta *prev = nfp_meta_prev(meta); + u32 imm_lo, imm_hi; + u8 dst; + + dst = prev->insn.dst_reg * 2; + imm_lo = prev->insn.imm; + imm_hi = meta->insn.imm; + + wrp_immed(nfp_prog, reg_both(dst), imm_lo); + + /* mov is always 1 insn, load imm may be two, so try to use mov */ + if (imm_hi == imm_lo) + wrp_mov(nfp_prog, reg_both(dst + 1), reg_a(dst)); + else + wrp_immed(nfp_prog, reg_both(dst + 1), imm_hi); return 0; } static int imm_ld8(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) { - const struct bpf_insn *insn = &meta->insn; - meta->double_cb = imm_ld8_part2; - wrp_immed(nfp_prog, reg_both(insn->dst_reg * 2), insn->imm); - return 0; } |