Initial commit of Hyperscan

src/fdr/teddy_engine_description.cpp

@@ -0,0 +1,207 @@
+/*
+ * Copyright (c) 2015, 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.h"
+#include "fdr_internal.h"
+#include "fdr_compile_internal.h"
+#include "fdr_confirm.h"
+#include "ue2common.h"
+#include "hs_internal.h"
+#include "fdr_engine_description.h"
+#include "teddy_internal.h"
+#include "teddy_engine_description.h"
+#include "util/make_unique.h"
+
+#include <cmath>
+
+using namespace std;
+
+namespace ue2 {
+
+TeddyEngineDescription::TeddyEngineDescription(const TeddyEngineDef &def)
+    : EngineDescription(def.id, targetByArchFeatures(def.cpu_features),
+                        def.numBuckets, def.confirmPullBackDistance,
+                        def.confirmTopLevelSplit),
+      numMasks(def.numMasks), packed(def.packed) {}
+
+u32 TeddyEngineDescription::getDefaultFloodSuffixLength() const {
+    return numMasks;
+}
+
+bool TeddyEngineDescription::needConfirm(const vector<hwlmLiteral> &lits) const {
+    if (packed || lits.size() > getNumBuckets()) {
+        return true;
+    }
+    for (const auto &lit : lits) {
+        if (lit.s.size() > numMasks || !lit.msk.empty()) {
+            return true;
+        }
+    }
+    return false;
+}
+
+#include "teddy_autogen_compiler.cpp"
+
+static
+size_t maxFloodTailLen(const vector<hwlmLiteral> &vl) {
+    size_t max_flood_tail = 0;
+    for (const auto &lit : vl) {
+        const string &s = lit.s;
+        assert(!s.empty());
+        size_t j;
+        for (j = 1; j < s.length(); j++) {
+            if (s[s.length() - j - 1] != s[s.length() - 1]) {
+                break;
+            }
+        }
+        max_flood_tail = max(max_flood_tail, j);
+    }
+    return max_flood_tail;
+}
+
+/**
+ * \brief True if this Teddy engine is qualified to handle this set of literals
+ * on this target.
+ */
+static
+bool isAllowed(const vector<hwlmLiteral> &vl, const TeddyEngineDescription &eng,
+               const size_t max_lit_len, const target_t &target) {
+    if (!eng.isValidOnTarget(target)) {
+        DEBUG_PRINTF("%u disallowed: not valid on target\n", eng.getID());
+        return false;
+    }
+    if (eng.getNumBuckets() < vl.size() && !eng.packed) {
+        DEBUG_PRINTF("%u disallowed: num buckets < num lits and not packed\n",
+                     eng.getID());
+        return false;
+    }
+    if (eng.getNumBuckets() * TEDDY_BUCKET_LOAD < vl.size()) {
+        DEBUG_PRINTF("%u disallowed: too many lits for num buckets\n",
+                     eng.getID());
+        return false;
+    }
+    if (eng.numMasks > max_lit_len) {
+        DEBUG_PRINTF("%u disallowed: more masks than max lit len (%zu)\n",
+                     eng.getID(), max_lit_len);
+        return false;
+    }
+
+    if (vl.size() > 40) {
+        u32 n_small_lits = 0;
+        for (const auto &lit : vl) {
+            if (lit.s.length() < eng.numMasks) {
+                n_small_lits++;
+            }
+        }
+        if (n_small_lits * 5 > vl.size()) {
+            DEBUG_PRINTF("too many short literals (%u)\n", n_small_lits);
+            return false;
+        }
+    }
+
+    return true;
+}
+
+unique_ptr<TeddyEngineDescription>
+chooseTeddyEngine(const target_t &target, const vector<hwlmLiteral> &vl) {
+    vector<TeddyEngineDescription> descs;
+    getTeddyDescriptions(&descs);
+    const TeddyEngineDescription *best = nullptr;
+
+    const size_t max_lit_len = maxLen(vl);
+    const size_t max_flood_tail = maxFloodTailLen(vl);
+    DEBUG_PRINTF("%zu lits, max_lit_len=%zu, max_flood_tail=%zu\n", vl.size(),
+                 max_lit_len, max_flood_tail);
+
+    u32 best_score = 0;
+    for (size_t engineID = 0; engineID < descs.size(); engineID++) {
+        const TeddyEngineDescription &eng = descs[engineID];
+        if (!isAllowed(vl, eng, max_lit_len, target)) {
+            continue;
+        }
+
+        u32 score = 0;
+
+        // We prefer unpacked Teddy models.
+        if (!eng.packed) {
+            score += 100;
+        }
+
+        // If we're heavily loaded, we prefer to have more masks.
+        if (vl.size() > 4 * eng.getNumBuckets()) {
+            score += eng.numMasks * 4;
+        } else {
+            // Lightly loaded cases are great.
+            score += 100;
+        }
+
+        // We want enough masks to avoid becoming flood-prone.
+        if (eng.numMasks > max_flood_tail) {
+            score += 50;
+        }
+
+        // We prefer having 3 masks. 3 is just right.
+        score += 6 / (abs(3 - (int)eng.numMasks) + 1);
+
+        // We prefer cheaper, smaller Teddy models.
+        score += 16 / eng.getNumBuckets();
+
+        DEBUG_PRINTF("teddy %u: masks=%u, buckets=%u, packed=%u "
+                     "-> score=%u\n",
+                     eng.getID(), eng.numMasks, eng.getNumBuckets(),
+                     eng.packed ? 1U : 0U, score);
+
+        if (!best || score > best_score) {
+            best = &eng;
+            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<TeddyEngineDescription>(*best);
+}
+
+unique_ptr<TeddyEngineDescription> getTeddyDescription(u32 engineID) {
+    vector<TeddyEngineDescription> descs;
+    getTeddyDescriptions(&descs);
+
+    for (const auto &desc : descs) {
+        if (desc.getID() == engineID) {
+            return ue2::make_unique<TeddyEngineDescription>(desc);
+        }
+    }
+
+    return nullptr;
+}
+
+} // namespace ue2