From: Jie Meng <jmeng@fb.com>
To: <kpsingh@kernel.org>, <bpf@vger.kernel.org>, <ast@kernel.org>,
<andrii@kernel.org>, <daniel@iogearbox.net>
Cc: Jie Meng <jmeng@fb.com>
Subject: [PATCH bpf-next v5 0/3] bpf,x64: Use BMI2 for shifts
Date: Fri, 7 Oct 2022 13:23:46 -0700 [thread overview]
Message-ID: <20221007202348.1118830-1-jmeng@fb.com> (raw)
In-Reply-To: <CACYkzJ7gz8Y0JXgfs2vKG5nF98iS+UdqpM9Vk0OOnSfYvMdK4g@mail.gmail.com>
With baseline x64 instruction set, shift count can only be an immediate
or in %cl. The implicit dependency on %cl makes it necessary to shuffle
registers around and/or add push/pop operations.
BMI2 provides shift instructions that can use any general register as
the shift count, saving us instructions and a few bytes in most cases.
Suboptimal codegen when %ecx is source and/or destination is also
addressed and unnecessary instructions are removed.
test_progs: Summary: 267/1340 PASSED, 25 SKIPPED, 0 FAILED
test_progs-no_alu32: Summary: 267/1333 PASSED, 26 SKIPPED, 0 FAILED
test_verifier: Summary: 1367 PASSED, 636 SKIPPED, 0 FAILED (same result
with or without BMI2)
test_maps: OK, 0 SKIPPED
lib/test_bpf:
test_bpf: Summary: 1026 PASSED, 0 FAILED, [1014/1014 JIT'ed]
test_bpf: test_tail_calls: Summary: 10 PASSED, 0 FAILED, [10/10 JIT'ed]
test_bpf: test_skb_segment: Summary: 2 PASSED, 0 FAILED
---
v4 -> v5:
- More comments regarding instruction encoding
v3 -> v4:
- Fixed a regression when BMI2 isn't available
Jie Meng (3):
bpf,x64: avoid unnecessary instructions when shift dest is ecx
bpf,x64: use shrx/sarx/shlx when available
bpf: add selftests for lsh, rsh, arsh with reg operand
arch/x86/net/bpf_jit_comp.c | 106 ++++++++++++++++++---
tools/testing/selftests/bpf/verifier/jit.c | 24 +++++
2 files changed, 118 insertions(+), 12 deletions(-)
--
2.30.2
next prev parent reply other threads:[~2022-10-07 20:24 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-21 2:21 [PATCH bpf-next] bpf,x64: use shrx/sarx/shlx when available Jie Meng
2022-09-22 15:07 ` Daniel Borkmann
2022-09-24 0:32 ` [PATCH bpf-next v2 0/2] bpf,x64: Use BMI2 for shifts Jie Meng
2022-09-24 0:32 ` [PATCH bpf-next v2 1/2] bpf,x64: use shrx/sarx/shlx when available Jie Meng
2022-09-26 19:16 ` Daniel Borkmann
2022-09-27 0:38 ` Jie Meng
2022-09-27 9:45 ` Daniel Borkmann
2022-09-27 18:57 ` [PATCH bpf-next v3 0/3] bpf,x64: Use BMI2 for shifts Jie Meng
2022-09-27 18:57 ` [PATCH bpf-next v3 1/3] bpf,x64: avoid unnecessary instructions when shift dest is ecx Jie Meng
2022-09-27 18:58 ` [PATCH bpf-next v3 2/3] bpf,x64: use shrx/sarx/shlx when available Jie Meng
2022-09-27 18:58 ` [PATCH bpf-next v3 3/3] bpf: add selftests for lsh, rsh, arsh with reg operand Jie Meng
2022-10-02 5:11 ` [PATCH bpf-next v4 0/3] bpf,x64: Use BMI2 for shifts Jie Meng
2022-10-02 5:11 ` [PATCH bpf-next v4 1/3] bpf,x64: avoid unnecessary instructions when shift dest is ecx Jie Meng
2022-10-02 5:11 ` [PATCH bpf-next v4 2/3] bpf,x64: use shrx/sarx/shlx when available Jie Meng
2022-10-06 4:11 ` KP Singh
2022-10-07 3:14 ` Jie Meng
2022-10-07 18:11 ` KP Singh
2022-10-07 20:23 ` Jie Meng [this message]
2022-10-20 0:00 ` [PATCH bpf-next v5 0/3] bpf,x64: Use BMI2 for shifts patchwork-bot+netdevbpf
2022-10-07 20:23 ` [PATCH bpf-next v5 1/3] bpf,x64: avoid unnecessary instructions when shift dest is ecx Jie Meng
2022-10-07 20:23 ` [PATCH bpf-next v5 2/3] bpf,x64: use shrx/sarx/shlx when available Jie Meng
2022-10-07 20:23 ` [PATCH bpf-next v5 3/3] bpf: add selftests for lsh, rsh, arsh with reg operand Jie Meng
2022-10-02 5:11 ` [PATCH bpf-next v4 " Jie Meng
2022-09-24 0:32 ` [PATCH bpf-next v2 2/2] bpf: Add " Jie Meng
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