multiexp: tune which variants to use for which number of points

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moneromooo-monero 2018-08-27 13:23:57 +00:00
parent 8b4767221c
commit a110e6aa18
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GPG key ID: 686F07454D6CEFC3
2 changed files with 30 additions and 14 deletions

View file

@ -48,7 +48,7 @@ extern "C"
#define PERF_TIMER_START_BP(x) PERF_TIMER_START_UNIT(x, 1000000) #define PERF_TIMER_START_BP(x) PERF_TIMER_START_UNIT(x, 1000000)
#define STRAUS_SIZE_LIMIT 128 #define STRAUS_SIZE_LIMIT 232
#define PIPPENGER_SIZE_LIMIT 0 #define PIPPENGER_SIZE_LIMIT 0
namespace rct namespace rct
@ -77,11 +77,11 @@ static inline rct::key multiexp(const std::vector<MultiexpData> &data, size_t Hi
{ {
if (HiGi_size > 0) if (HiGi_size > 0)
{ {
static_assert(128 <= STRAUS_SIZE_LIMIT, "Straus in precalc mode can only be calculated till STRAUS_SIZE_LIMIT"); static_assert(232 <= STRAUS_SIZE_LIMIT, "Straus in precalc mode can only be calculated till STRAUS_SIZE_LIMIT");
return HiGi_size <= 128 && data.size() == HiGi_size ? straus(data, straus_HiGi_cache, 0) : pippenger(data, pippenger_HiGi_cache, HiGi_size, get_pippenger_c(data.size())); return HiGi_size <= 232 && data.size() == HiGi_size ? straus(data, straus_HiGi_cache, 0) : pippenger(data, pippenger_HiGi_cache, HiGi_size, get_pippenger_c(data.size()));
} }
else else
return data.size() <= 64 ? straus(data, NULL, 0) : pippenger(data, NULL, 0, get_pippenger_c(data.size())); return data.size() <= 95 ? straus(data, NULL, 0) : pippenger(data, NULL, 0, get_pippenger_c(data.size()));
} }
static inline bool is_reduced(const rct::key &scalar) static inline bool is_reduced(const rct::key &scalar)

View file

@ -79,6 +79,25 @@ extern "C"
// Best/cached Straus Straus Straus Straus Straus Straus Straus Straus Pip Pip Pip Pip // Best/cached Straus Straus Straus Straus Straus Straus Straus Straus Pip Pip Pip Pip
// Best/uncached Straus Straus Straus Straus Straus Straus Pip Pip Pip Pip Pip Pip // Best/uncached Straus Straus Straus Straus Straus Straus Pip Pip Pip Pip Pip Pip
// New timings:
// Pippenger:
// 2/1 always
// 3/2 at ~13
// 4/3 at ~29
// 5/4 at ~83
// 6/5 < 200
// 7/6 at ~470
// 8/7 at ~1180
// 9/8 at ~2290
// Cached Pippenger:
// 6/5 < 200
// 7/6 at 460
// 8/7 at 1180
// 9/8 at 2300
//
// Cached Straus/Pippenger cross at 232
//
namespace rct namespace rct
{ {
@ -543,16 +562,13 @@ skipfirst:
size_t get_pippenger_c(size_t N) size_t get_pippenger_c(size_t N)
{ {
// uncached: 2:1, 4:2, 8:2, 16:3, 32:4, 64:4, 128:5, 256:6, 512:7, 1024:7, 2048:8, 4096:9 if (N <= 13) return 2;
// cached: 2:1, 4:2, 8:2, 16:3, 32:4, 64:4, 128:5, 256:6, 512:7, 1024:7, 2048:8, 4096:9 if (N <= 29) return 3;
if (N <= 2) return 1; if (N <= 83) return 4;
if (N <= 8) return 2; if (N <= 185) return 5;
if (N <= 16) return 3; if (N <= 465) return 6;
if (N <= 64) return 4; if (N <= 1180) return 7;
if (N <= 128) return 5; if (N <= 2295) return 8;
if (N <= 256) return 6;
if (N <= 1024) return 7;
if (N <= 2048) return 8;
return 9; return 9;
} }