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rust-secp256k1-unsafe-fast
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Improve default settings and documentation

This commit is contained in:
Christian Reitter 2024-04-28 20:46:46 +02:00
parent 9281022f1d
commit 36af387bea
1 changed files with 25 additions and 24 deletions
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49
secp256k1-sys/build.rs
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@ -23,9 +23,9 @@ fn main() {
.flag_if_supported("-Wno-unused-parameter") // patching out printf causes this warning
.define("SECP256K1_API", Some(""))
.define("ENABLE_MODULE_ECDH", Some("1"))
.define("ENABLE_MODULE_SCHNORRSIG", Some("1"))
.define("ENABLE_MODULE_EXTRAKEYS", Some("1"))
.define("ENABLE_MODULE_ELLSWIFT", Some("1"))
.define("ENABLE_MODULE_SCHNORRSIG", Some("0"))
.define("ENABLE_MODULE_EXTRAKEYS", Some("0"))
.define("ENABLE_MODULE_ELLSWIFT", Some("0"))
// upstream sometimes introduces calls to printf, which we cannot compile
// with WASM due to its lack of libc. printf is never necessary and we can
// just #define it away.
@ -42,22 +42,18 @@ fn main() {
// going from the default 4 to 8 is a huge performance increase
// when combined with other optimizations
base_config.define("ECMULT_GEN_PREC_BITS", Some("8"));
// base_config.define("ECMULT_GEN_PREC_BITS", Some("8"));
// TODO highly experimental
// non-standard optimization
// slow compilation
// base_config.define("ECMULT_GEN_PREC_BITS", Some("16"));
base_config.define("ECMULT_GEN_PREC_BITS", Some("16"));
// minor factor, the 15 default is already optimized
// ECMULT_WINDOW_SIZE has only a minor performance impact
// the default value of 15 is already optimized and would be acceptable
// values 14, 16, 17 don't result in a meaningful speedup
base_config.define("ECMULT_WINDOW_SIZE", Some("15")); // This is the default in the configure file (`auto`)
// TODO do some fine tuning for a slightly higher than default ECMULT_WINDOW_SIZE
// base_config.define("ECMULT_WINDOW_SIZE", Some("17"));
// base_config.define("ECMULT_WINDOW_SIZE", Some("18"));
// too large
// base_config.define("ECMULT_WINDOW_SIZE", Some("22"));
// base_config.define("ECMULT_WINDOW_SIZE", Some("19"));
}
base_config.define("USE_EXTERNAL_DEFAULT_CALLBACKS", Some("1"));
#[cfg(feature = "recovery")]
@ -75,20 +71,27 @@ fn main() {
.file("depend/secp256k1/src/precomputed_ecmult.c")
.file("depend/secp256k1/src/secp256k1.c");
// default CC is gcc on the tested system
// GCC 12.2 slightly faster than clang-18 for the unmodified code?
// observation: GCC 12.2 slightly faster than clang-18 for the unmodified code
// observation: clang-14 is slightly faster than gcc 12.2 for the modified code
// for the modified code, clang is slightly faster?
// on the tested system, the compilers don't default to use some -fstack-protector level
// therefore the use of -fno-stack-protector isn't necessary
// // force clang
// force use of clang
base_config.compiler("clang");
// // gcc is faster without native CPU settings on a Ryzen Zen 3 desktop CPU
// gcc 12.2 is faster without this setting on Ryzen Zen 3/4 CPUs
base_config.flag("-march=native");
// doesn't work as-is
// doesn't work yet
// relevant:
// RUSTFLAGS="-Clink-args=-fuse-ld=lld"
// installing the lld tool package
// for lto=thin, there are problems with "Opaque pointers are only supported in -opaque-pointers mode"
// for lto=fat, there are some problems with "error: undefined symbol"
// base_config.flag("-flto=thin");
// base_config.flag("-flto=fat");
// shouldn't do much
base_config.define("NDEBUG", Some(""));
@ -106,6 +109,7 @@ fn main() {
// -O3 seems to be better than -O2 for clang
// -O3 is already the default for --release builds
// set anyway so that rust non-release builds don't fall back to -O1 here
// base_config.flag("-O3");
base_config.flag("-O3");
// base_config.flag("-O1");
@ -115,12 +119,11 @@ fn main() {
// the default seems to set -gdwarf-4
// slightly worse on gcc?
// slightly better on clang-18 ?
// base_config.flag("-g0");
base_config.flag("-g0");
// potential minor improvement
// to counteract the -fno-omit-frame-pointer
// base_config.flag("-fomit-frame-pointer");
base_config.flag("-fomit-frame-pointer");
if base_config.try_compile("libsecp256k1.a").is_err() {
// Some embedded platforms may not have, eg, string.h available, so if the build fails
@ -129,6 +132,4 @@ fn main() {
// base_config.include("wasm/wasm-sysroot");
// base_config.compile("libsecp256k1.a");
}
}