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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Nicolas Schichan <nschichan@freebox.fr>
Cc: Russell King <linux@arm.linux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	Mircea Gherzan <mgherzan@gmail.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH net-next V2] ARM: net: support BPF_ALU | BPF_MOD instructions in the BPF JIT.
Date: Fri, 2 Oct 2015 08:25:20 -0700	[thread overview]
Message-ID: <20151002152519.GA1619@Alexeis-MBP.westell.com> (raw)
In-Reply-To: <1443798407-19154-1-git-send-email-nschichan@freebox.fr>

On Fri, Oct 02, 2015 at 05:06:47PM +0200, Nicolas Schichan wrote:
> For ARMv7 with UDIV instruction support, generate an UDIV instruction
> followed by an MLS instruction.
> 
> For other ARM variants, generate code calling a C wrapper similar to
> the jit_udiv() function used for BPF_ALU | BPF_DIV instructions.
> 
> Some performance numbers reported by the test_bpf module (the duration
> per filter run is reported in nanoseconds, between "jitted:<x>" and
> "PASS":
> 
> ARMv7 QEMU nojit:	test_bpf: #3 DIV_MOD_KX jited:0 2196 PASS
> ARMv7 QEMU jit:		test_bpf: #3 DIV_MOD_KX jited:1 104 PASS
> ARMv5 QEMU nojit:	test_bpf: #3 DIV_MOD_KX jited:0 2176 PASS
> ARMv5 QEMU jit:		test_bpf: #3 DIV_MOD_KX jited:1 1104 PASS
> ARMv5 kirkwood nojit:	test_bpf: #3 DIV_MOD_KX jited:0 1103 PASS
> ARMv5 kirkwood jit:	test_bpf: #3 DIV_MOD_KX jited:1 311 PASS
> 
> Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>

run-time check for zero is there, so looks good to me
Acked-by: Alexei Starovoitov <ast@kernel.org>


  reply	other threads:[~2015-10-02 15:25 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-02 15:06 Nicolas Schichan
2015-10-02 15:25 ` Alexei Starovoitov [this message]
2015-10-05 14:03 ` David Miller

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