netdev - Re: [PATCH bpf] bpf, x64: increase number of passes

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Message-ID: <20180307224837.w27anwe2csgbnlg2@ast-mbp>
Date:   Wed, 7 Mar 2018 14:48:39 -0800
From:   Alexei Starovoitov <alexei.starovoitov@...il.com>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     ast@...nel.org, netdev@...r.kernel.org
Subject: Re: [PATCH bpf] bpf, x64: increase number of passes

On Wed, Mar 07, 2018 at 10:10:01PM +0100, Daniel Borkmann wrote:
> In Cilium some of the main programs we run today are hitting 9 passes
> on x64's JIT compiler, and we've had cases already where we surpassed
> the limit where the JIT then punts the program to the interpreter
> instead, leading to insertion failures due to CONFIG_BPF_JIT_ALWAYS_ON
> or insertion failures due to the prog array owner being JITed but the
> program to insert not (both must have the same JITed/non-JITed property).
> 
> One concrete case the program image shrunk from 12,767 bytes down to
> 10,288 bytes where the image converged after 16 steps. I've measured
> that this took 340us in the JIT until it converges on my i7-6600U. Thus,
> increase the original limit we had from day one where the JIT covered
> cBPF only back then before we run into the case (as similar with the
> complexity limit) where we trip over this and hit program rejections.
> Also add a cond_resched() into the compilation loop, the JIT process
> runs without any locks and may sleep anyway.
> 
> Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
> Acked-by: Alexei Starovoitov <ast@...nel.org>

Applied to bpf tree, Thanks Daniel!