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/*
* Copyright (c) 2015-2017, Intel Corporation
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Intel Corporation nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "fdr_compile_internal.h"
#include "fdr_engine_description.h"
#include "hs_compile.h"
#include "util/target_info.h"
#include "util/compare.h" // for ourisalpha()
#include "util/make_unique.h"
#include <cassert>
#include <cstdlib>
#include <map>
#include <string>
using namespace std;
namespace ue2 {
FDREngineDescription::FDREngineDescription(const FDREngineDef &def)
: EngineDescription(def.id, targetByArchFeatures(def.cpu_features),
def.numBuckets),
schemeWidth(def.schemeWidth), stride(0), bits(0) {}
u32 FDREngineDescription::getDefaultFloodSuffixLength() const {
// rounding up, so that scheme width 32 and 6 buckets is 6 not 5!
// the +1 avoids pain due to various reach choices
return ((getSchemeWidth() + getNumBuckets() - 1) / getNumBuckets()) + 1;
}
void getFdrDescriptions(vector<FDREngineDescription> *out) {
static const FDREngineDef def = {0, 64, 8, 0};
out->clear();
out->emplace_back(def);
}
static
u32 findDesiredStride(size_t num_lits, size_t min_len, size_t min_len_count) {
u32 desiredStride = 1; // always our safe fallback
if (min_len > 1) {
if (num_lits < 250) {
// small cases we just go for it
desiredStride = min_len;
} else if (num_lits < 800) {
// intermediate cases
desiredStride = min_len - 1;
} else if (num_lits < 5000) {
// for larger but not huge sizes, go to stride 2 only if we have at
// least minlen 3
desiredStride = MIN(min_len - 1, 2);
}
}
// patch if count is quite large - a ton of length 2 literals can
// break things
#ifdef TRY_THIS_LATER
if ((min_len == 2) && (desiredStride == 2) && (min_len_count > 20)) {
desiredStride = 1;
}
#endif
// patch stuff just for the stride 4 case; don't let min_len=4,
// desiredStride=4 through as even a few length 4 literals can break things
// (far more fragile)
if ((min_len == 4) && (desiredStride == 4) && (min_len_count > 2)) {
desiredStride = 2;
}
return desiredStride;
}
unique_ptr<FDREngineDescription> chooseEngine(const target_t &target,
const vector<hwlmLiteral> &vl,
bool make_small) {
vector<FDREngineDescription> allDescs;
getFdrDescriptions(&allDescs);
// find desired stride
size_t count;
size_t msl = minLenCount(vl, &count);
u32 desiredStride = findDesiredStride(vl.size(), msl, count);
DEBUG_PRINTF("%zu lits, msl=%zu, desiredStride=%u\n", vl.size(), msl,
desiredStride);
FDREngineDescription *best = nullptr;
u32 best_score = 0;
FDREngineDescription &eng = allDescs[0];
for (u32 domain = 9; domain <= 15; domain++) {
for (size_t stride = 1; stride <= 4; stride *= 2) {
// to make sure that domains >=14 have stride 1 according to origin
if (domain > 13 && stride > 1) {
continue;
}
if (!eng.isValidOnTarget(target)) {
continue;
}
if (msl < stride) {
continue;
}
u32 score = 100;
score -= absdiff(desiredStride, stride);
if (stride <= desiredStride) {
score += stride;
}
u32 effLits = vl.size(); /* * desiredStride;*/
u32 ideal;
if (effLits < eng.getNumBuckets()) {
if (stride == 1) {
ideal = 8;
} else {
ideal = 10;
}
} else if (effLits < 20) {
ideal = 10;
} else if (effLits < 100) {
ideal = 11;
} else if (effLits < 1000) {
ideal = 12;
} else if (effLits < 10000) {
ideal = 13;
} else {
ideal = 15;
}
if (ideal != 8 && eng.schemeWidth == 32) {
ideal += 1;
}
if (make_small) {
ideal -= 2;
}
if (stride > 1) {
ideal++;
}
DEBUG_PRINTF("effLits %u\n", effLits);
if (target.is_atom_class() && !make_small && effLits < 4000) {
/* Unless it is a very heavy case, we want to build smaller
* tables on lightweight machines due to their small caches. */
ideal -= 2;
}
score -= absdiff(ideal, domain);
DEBUG_PRINTF("fdr %u: width=%u, domain=%u, buckets=%u, stride=%zu "
"-> score=%u\n",
eng.getID(), eng.schemeWidth, domain,
eng.getNumBuckets(), stride, score);
if (!best || score > best_score) {
eng.bits = domain;
eng.stride = stride;
best = ŋ
best_score = score;
}
}
}
if (!best) {
DEBUG_PRINTF("failed to find engine\n");
return nullptr;
}
DEBUG_PRINTF("using engine %u\n", best->getID());
return ue2::make_unique<FDREngineDescription>(*best);
}
SchemeBitIndex FDREngineDescription::getSchemeBit(BucketIndex b,
PositionInBucket p) const {
assert(p < getBucketWidth(b));
SchemeBitIndex sbi = p * getNumBuckets() + b;
assert(sbi < getSchemeWidth());
return sbi;
}
u32 FDREngineDescription::getBucketWidth(BucketIndex) const {
u32 sw = getSchemeWidth();
u32 nm = getNumBuckets();
assert(sw % nm == 0);
return sw/nm;
}
unique_ptr<FDREngineDescription> getFdrDescription(u32 engineID) {
vector<FDREngineDescription> allDescs;
getFdrDescriptions(&allDescs);
if (engineID >= allDescs.size()) {
return nullptr;
}
return ue2::make_unique<FDREngineDescription>(allDescs[engineID]);
}
} // namespace ue2
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