File size: 3,947 Bytes
bbb6388 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 | // src/spec/controller_test.cpp - plan v0.3 P6: the speculation controller's decisions (no model, no GPU).
#include "strata/spec/controller.hpp"
#include <cstdio>
using namespace strata::spec;
namespace {
int g_fail = 0;
void check(bool ok, const char* what) {
if (!ok) { std::fprintf(stderr, "FAIL: %s\n", what); ++g_fail; }
}
const char* name(Source s) { return s == Source::Mtp ? "mtp" : s == Source::Lookup ? "lookup" : "none"; }
} // namespace
int main() {
{ // priors (MTP 0.86 per draft): MTP with a short-to-medium window beats plain decoding
Controller c;
const Choice ch = c.choose(0, 0, true);
check(ch.source == Source::Mtp && ch.k >= 2 && ch.k <= 5, "MTP chosen with k in 2..5 at the prior");
std::printf("prior: %s k=%d expected %.2f tokens, %.1f tok/s (plain %.1f)\n", name(ch.source), ch.k,
ch.expected_tokens, 1000 * ch.tokens_per_ms, 1000.0 / c.cost().step_ms(0, false));
}
{ // a drafter that keeps missing its first token is switched off
Controller c;
Choice ch = c.choose(0, 0, true);
for (int i = 0; i < 400; ++i) { c.observe(ch, 0, 0); ch = c.choose(0, 0, true); if (ch.source == Source::None) break; }
check(ch.source == Source::None, "persistent rejection turns speculation off");
std::printf("after rejections: %s, p0 %.2f\n", name(ch.source), c.mtp_accept(0));
}
{ // a long lookup match beats MTP; how LONG a window pays depends on what a wide verify costs
Controller c;
const Choice ch = c.choose(8, 20, true);
check(ch.source == Source::Lookup, "long lookup match preferred over MTP");
std::printf("long lookup match, measured costs: %s k=%d expected %.2f, %.1f tok/s\n", name(ch.source), ch.k,
ch.expected_tokens, 1000 * ch.tokens_per_ms);
CostModel cheap; // a verify pass whose cost barely grows with width
cheap.dense_ratio = {1.0, 1.02, 1.04, 1.06, 1.08, 1.1, 1.12, 1.14, 1.16};
cheap.hit_rate = 0.95;
Controller c2(cheap);
const Choice ch2 = c2.choose(8, 20, true);
check(ch2.source == Source::Lookup && ch2.k == 8, "cheap wide verify takes the whole lookup window");
std::printf("long lookup match, cheap wide verify: %s k=%d expected %.2f, %.1f tok/s\n", name(ch2.source),
ch2.k, ch2.expected_tokens, 1000 * ch2.tokens_per_ms);
}
{ // a bare trigram match, no MTP: not worth a verify window
Controller c;
const Choice ch = c.choose(8, 3, false);
check(ch.source == Source::None, "short lookup match alone is not used");
}
{ // perfect acceptance is learned and widens the window
Controller c;
Choice ch = c.choose(0, 0, true);
const int k0 = ch.k;
for (int i = 0; i < 400; ++i) { c.observe(ch, ch.k, 0); ch = c.choose(0, 0, true); }
check(ch.k > k0 && c.mtp_accept(0) > 0.99, "full acceptance learned and the window widens");
std::printf("after full acceptance: %s k=%d (was %d), p0 %.3f\n", name(ch.source), ch.k, k0, c.mtp_accept(0));
}
std::printf("\nMTP acceptance -> choice (default cost model):\n");
for (double p : {0.5, 0.6, 0.7, 0.8, 0.86, 0.9, 0.95}) {
Controller c;
Choice ch = c.choose(0, 0, true);
for (int i = 0; i < 2000; ++i) { // feed a stream with iid acceptance p per position
int acc = 0;
unsigned r = 2654435761u * (unsigned) (i + 1);
while (acc < ch.k && ((r = r * 1103515245u + 12345u) >> 8) % 1000 < p * 1000) ++acc;
c.observe(ch, acc, 0);
ch = c.choose(0, 0, true);
}
std::printf(" p=%.2f: %s k=%d, %.1f tok/s\n", p, name(ch.source), ch.k, 1000 * ch.tokens_per_ms);
}
std::printf("controller tests: %s\n", g_fail ? "FAILED" : "OK");
return g_fail ? 1 : 0;
}
|