[WireGuard] News about MIPS and ARM optimized code?

[Baptiste Jonglez]

Nice work!  I had tried to write chacha20_generic_block in MIPS assembly,
but I got confused with endianness issues and the code didn't work in the
end.

Is your code available somewhere?  I'd be happy to test on a variety of
MIPS routers.

On Fri, Sep 09, 2016 at 01:46:11PM +0000, René van Dorst wrote:
> Duo the misaligned data fetching function like poly1305 causes regression on
> the mips.
> 
> 	h0 += (le32_to_cpuvp(src +  0) >> 0) & 0x3ffffff;
> 		h1 += (le32_to_cpuvp(src +  3) >> 2) & 0x3ffffff;
> 		h2 += (le32_to_cpuvp(src +  6) >> 4) & 0x3ffffff;
> 		h3 += (le32_to_cpuvp(src +  9) >> 6) & 0x3ffffff;
> 		h4 += (le32_to_cpuvp(src + 12) >> 8) | hibit;
> 
> 
> Had 26MBit now +42.
> 
> root at lede:~# iperf3 -c 10.0.0.1 -i 10
> Connecting to host 10.0.0.1, port 5201
> [  4] local 10.0.0.2 port 36216 connected to 10.0.0.1 port 5201
> [ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
> [  4]   0.00-10.08  sec  51.2 MBytes  42.7 Mbits/sec    0    171 KBytes
> - - - - - - - - - - - - - - - - - - - - - - - - -
> [ ID] Interval           Transfer     Bandwidth       Retr
> [  4]   0.00-10.08  sec  51.2 MBytes  42.7 Mbits/sec    0             sender
> [  4]   0.00-10.08  sec  51.2 MBytes  42.7 Mbits/sec                  receiver
> 
> iperf Done.
> root at lede:~# iperf3 -c 10.0.0.1 -u -b 1G -i 10
> Connecting to host 10.0.0.1, port 5201
> [  4] local 10.0.0.2 port 60714 connected to 10.0.0.1 port 5201
> [ ID] Interval           Transfer     Bandwidth       Total Datagrams
> [  4]   0.00-10.00  sec  56.3 MBytes  47.2 Mbits/sec  7209
> - - - - - - - - - - - - - - - - - - - - - - - - -
> [ ID] Interval           Transfer     Bandwidth       Jitter    Lost/Total
> Datagrams
> [  4]   0.00-10.00  sec  56.3 MBytes  47.2 Mbits/sec  0.034 ms  0/7209 (0%)
> [  4] Sent 7209 datagrams
> 
> iperf Done.
> root at lede:~#
> 
> 
> Work is not done yet but a good start.
> 
> Greats,
> 
> René van Dorst.
> 
> Quoting René van Dorst <opensource at vdorst.com>:
> 
> >I did try to write some MIPS32r2 code.
> >I wrote the chacha20_keysetup, chacha20_generic_block and
> >poly1305_generic_blocks in assembly.
> >Tried to load all needed variables in the registers. Which should reduce
> >the memory overhead.
> >But it is very difficult for me to do code profiling and/or isolate the
> >code and make some benchmark programs like supercop.
> >So testing was simple. Crosscompile the code. Copy and load the module on
> >the target. Run setup script and iperf.
> >
> >#ifdef CONFIG_CPU_MIPS32_R2
> >asmlinkage void chacha20_keysetup(struct chacha20_ctx *ctx, const u8
> >key[static 32], const u8 nonce[static 8]);
> >asmlinkage void chacha20_generic_block(struct chacha20_ctx *ctx);
> >asmlinkage unsigned int poly1305_generic_blocks(struct poly1305_ctx *ctx,
> >const u8 *src, unsigned int srclen, u32 hibit);
> >#endif
> >
> >But the speed is equal or less on my TP WR1043ND device which is a
> >MIPS32r2 24kc big endian.
> >So GCC does a good job. Also 24kc has no special CoProcessors or FPU.
> >
> >Most improvement what I had it to change the buildroot default
> >optimization -Os to -O2.
> >This gives around 1-3% speed improvement.
> >
> >ideas:
> >- remove the little endian parts on the MIPS.
> >  Offcourse do it also on the other side.
> >  On this device I can't switch endian.
> >  But I did not see any improvements. Need 2 instruction for swapping
> >32bit register.
> >  After a quick calculation it could save around 0.4% which is ~0.1MBit/s
> >on this device.
> >
> >Greats,
> >
> >René van Dorst.
> >
> >_______________________________________________
> >WireGuard mailing list
> >WireGuard at lists.zx2c4.com
> >http://lists.zx2c4.com/mailman/listinfo/wireguard
> 
> 
> 
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