commit a77616f6056a9dbb5722600ff2465d8ec5b3d063 Author: Yawning Angel yawning@schwanenlied.me Date: Mon Aug 17 18:41:41 2015 +0000

Enable ed25519-donna's SSE2 code when possible for 32 bit x86.

This probably requires the user to manually set CFLAGS, but should result in a net gain on 32 bit x86. Enabling SSE2 support would be possible on x86_64, but will result in slower performance.

Implements feature #16535. --- changes/feature16535 | 4 ++++ src/ext/ed25519/donna/README.tor | 4 ++++ src/ext/ed25519/donna/ed25519-donna-portable.h | 10 ++++++++++ 3 files changed, 18 insertions(+)

diff --git a/changes/feature16535 b/changes/feature16535 new file mode 100644 index 0000000..3df46b6 --- /dev/null +++ b/changes/feature16535 @@ -0,0 +1,4 @@ + o Minor features (performance) + - Improve the runtime speed of Ed25519 operations and Curve25519 keypair + generation when built targeting 32 bit x86 platforms with SSE2 + available. Implements ticket 16535. diff --git a/src/ext/ed25519/donna/README.tor b/src/ext/ed25519/donna/README.tor index 2bb0efc..026d180 100644 --- a/src/ext/ed25519/donna/README.tor +++ b/src/ext/ed25519/donna/README.tor @@ -40,3 +40,7 @@ as of 8757bd4cd209cb032853ece0ce413f122eef212c. * On non-x86 targets, GCC's Stack Protector dislikes variables that have alignment constraints greater than that of other primitive types. The `ALIGN` macro is thus no-oped for all non-SSE2 builds. + + * On 32 bit x86 targets that the compiler thinks supports SSE2, always + enable SSE2 support by force defining ED25519_SSE2 (x86_64 would also + always support this, but that code path is slower). diff --git a/src/ext/ed25519/donna/ed25519-donna-portable.h b/src/ext/ed25519/donna/ed25519-donna-portable.h index 9ec83b8..1cd644c 100644 --- a/src/ext/ed25519/donna/ed25519-donna-portable.h +++ b/src/ext/ed25519/donna/ed25519-donna-portable.h @@ -158,6 +158,16 @@ static inline void U64TO8_LE(unsigned char *p, const uint64_t v) { #define ALIGN(x) #endif

+/* Tor: Force enable SSE2 on 32 bit x86 systems if the compile target + * architecture supports it. This is not done on x86-64 as the non-SSE2 + * code benchmarks better, at least on Haswell. + */ +#if defined(__SSE2__) && !defined(CPU_X86_64) + /* undef in case it's manually specified... */ + #undef ED25519_SSE2 + #define ED25519_SSE2 +#endif + #include <stdlib.h> #include <string.h>