From: Jiong Wang <jiong.wang@netronome.com>
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: alexei.starovoitov@gmail.com, daniel@iogearbox.net,
Jiong Wang <jiong.wang@netronome.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org,
oss-drivers@netronome.com
Subject: Re: [PATCH v3 bpf-next 08/19] bpf: insert explicit zero extension insn when hardware doesn't do it implicitly
Date: Mon, 15 Apr 2019 12:24:32 +0100 [thread overview]
Message-ID: <874l6zfr4f.fsf@netronome.com> (raw)
In-Reply-To: <1555322953.xj35xt2bjs.naveen@linux.ibm.com>
Naveen N. Rao writes:
> Naveen N. Rao wrote:
>>> It is then for all back-ends to decide how to use such information to
>>> eliminate unnecessary zero extension code-gen during JIT compilation.
>>>
>>> One approach is:
>>> 1. Verifier insert explicit zero extension for those instructions that
>>> need zero extension.
>>> 2. All JIT back-ends do NOT generate zero extension for sub-register
>>> write any more.
>>
>> Is it possible to instead give a hint to the JIT back-ends on the
>> instructions needing zero-extension? That would help in case of
>> architectures that have single/more-optimal instruction for zero
>> extension, compared to having to emit 2 instructions with the current
>> approach.
>
> I just noticed your discussion with Alexei on RFC v1 after posting this.
> I agree that this can be looked into subsequently -- either a new
> instruction, or detecting this during JIT.
Thanks Naveen.
It will be great if you could test the latest set on PowerPC to see if
there is any regression for example for those under test_progs and
test_verifier.
And it will be even greater if you also use latest llvm snapshot for the
testing, which then will enable test_progs_32 etc.
Thanks.
Regards,
Jiong
next prev parent reply other threads:[~2019-04-15 11:24 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-12 21:59 [PATCH v3 bpf-next 00/19] bpf: eliminate zero extensions for sub-register writes Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 01/19] bpf: refactor propagate_liveness to eliminate duplicated for loop Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 02/19] bpf: refactor propagate_liveness to eliminate code redundance Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 03/19] bpf: factor out reg and stack slot propagation into "propagate_liveness_reg" Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 04/19] bpf: refactor "check_reg_arg" to eliminate code redundancy Jiong Wang
2019-04-13 0:12 ` Alexei Starovoitov
2019-04-13 7:00 ` Jiong Wang
2019-04-15 5:41 ` Alexei Starovoitov
2019-04-12 21:59 ` [PATCH v3 bpf-next 05/19] bpf: split read liveness into REG_LIVE_READ64 and REG_LIVE_READ32 Jiong Wang
2019-04-13 1:07 ` Jakub Kicinski
2019-04-13 6:39 ` Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 06/19] bpf: mark lo32 writes that should be zero extended into hi32 Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 07/19] bpf: reduce false alarm by refining helper call arg types Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 08/19] bpf: insert explicit zero extension insn when hardware doesn't do it implicitly Jiong Wang
2019-04-15 9:59 ` Naveen N. Rao
2019-04-15 10:11 ` Naveen N. Rao
2019-04-15 11:24 ` Jiong Wang [this message]
2019-04-15 18:21 ` Naveen N. Rao
2019-04-15 19:28 ` Jiong Wang
2019-04-16 6:41 ` Naveen N. Rao
2019-04-16 7:47 ` [oss-drivers] " Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 09/19] bpf: introduce new bpf prog load flags "BPF_F_TEST_RND_HI32" Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 10/19] bpf: randomize high 32-bit when BPF_F_TEST_RND_HI32 is set Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 11/19] libbpf: add "prog_flags" to bpf_program/bpf_prog_load_attr/bpf_load_program_attr Jiong Wang
2019-04-13 1:08 ` Jakub Kicinski
2019-04-12 21:59 ` [PATCH v3 bpf-next 12/19] selftests: enable hi32 randomization for all tests Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 13/19] arm: bpf: eliminate zero extension code-gen Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 14/19] powerpc: " Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 15/19] s390: " Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 16/19] sparc: " Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 17/19] x32: " Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 18/19] riscv: " Jiong Wang
2019-04-12 21:59 ` [PATCH v3 bpf-next 19/19] nfp: " Jiong Wang
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