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Reduce memory use of statistic collection (#6513)

This commit is contained in:
Geza Lore 2025-09-30 13:06:57 +02:00 committed by GitHub
parent c5f3192588
commit b902e4bcf5
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GPG Key ID: B5690EEEBB952194
2 changed files with 28 additions and 12 deletions
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33
src/V3FuncOpt.cpp
View File

@ -170,14 +170,25 @@ public:
static AstConcat* apply(AstConcat* rootp) { return balance(rootp); }
};
struct FuncOptStats final {
// STATE - Statistic tracking
VDouble0 m_balancedConcats; // Number of concatenations balanced
VDouble0 m_concatSplits; // Number of splits in assignments with Concat on RHS
FuncOptStats() = default;
~FuncOptStats() {
V3Stats::addStat("Optimizations, FuncOpt concat trees balanced", m_balancedConcats);
V3Stats::addStat("Optimizations, FuncOpt concat splits", m_concatSplits);
}
};
class FuncOptVisitor final : public VNVisitor {
// NODE STATE
// AstNodeAssign::user() -> bool. Already checked, safe to split. Omit expensive check.
// AstConcat::user() -> bool. Already balanced.
// STATE - Statistic tracking
VDouble0 m_balancedConcats; // Number of concatenations balanced
VDouble0 m_concatSplits; // Number of splits in assignments with Concat on RHS
// STATE
FuncOptStats& m_stats; // Statistics
// True for e.g.: foo = foo >> 1; or foo[foo[0]] = ...;
static bool readsLhs(AstNodeAssign* nodep) {
@ -256,7 +267,7 @@ class FuncOptVisitor final : public VNVisitor {
// Ok, actually split it now
UINFO(5, "splitConcat optimizing " << nodep);
++m_concatSplits;
++m_stats.m_concatSplits;
// The 2 parts and their offsets
AstNodeExpr* const rrp = rhsp->rhsp()->unlinkFrBack();
AstNodeExpr* const rlp = rhsp->lhsp()->unlinkFrBack();
@ -294,7 +305,7 @@ class FuncOptVisitor final : public VNVisitor {
if (v3Global.opt.fFuncBalanceCat() && !nodep->user1() && !VN_IS(nodep->backp(), Concat)) {
if (AstConcat* const newp = BalanceConcatTree::apply(nodep)) {
UINFO(5, "balanceConcat optimizing " << nodep);
++m_balancedConcats;
++m_stats.m_balancedConcats;
nodep->replaceWith(newp);
VL_DO_DANGLING(pushDeletep(nodep), nodep);
newp->user1(true); // Must not attempt again.
@ -308,14 +319,13 @@ class FuncOptVisitor final : public VNVisitor {
void visit(AstNode* nodep) override { iterateChildren(nodep); }
// CONSTRUCTORS
explicit FuncOptVisitor(AstCFunc* funcp) { iterateChildren(funcp); }
~FuncOptVisitor() override {
V3Stats::addStatSum("Optimizations, FuncOpt concat trees balanced", m_balancedConcats);
V3Stats::addStatSum("Optimizations, FuncOpt concat splits", m_concatSplits);
explicit FuncOptVisitor(FuncOptStats& stats, AstCFunc* funcp)
: m_stats{stats} {
iterateChildren(funcp);
}
public:
static void apply(AstCFunc* funcp) { FuncOptVisitor{funcp}; }
static void apply(FuncOptStats& stats, AstCFunc* funcp) { FuncOptVisitor{stats, funcp}; }
};
//######################################################################
@ -324,12 +334,13 @@ void V3FuncOpt::funcOptAll(AstNetlist* nodep) {
UINFO(2, __FUNCTION__ << ":");
{
const VNUser1InUse user1InUse;
FuncOptStats stats;
for (AstNodeModule *modp = nodep->modulesp(), *nextModp; modp; modp = nextModp) {
nextModp = VN_AS(modp->nextp(), NodeModule);
for (AstNode *stmtp = modp->stmtsp(), *nextStmtp; stmtp; stmtp = nextStmtp) {
nextStmtp = stmtp->nextp();
if (AstCFunc* const cfuncp = VN_CAST(stmtp, CFunc)) {
FuncOptVisitor::apply(cfuncp);
FuncOptVisitor::apply(stats, cfuncp);
}
}
}

7
src/V3StatsReport.cpp
View File

@ -160,7 +160,12 @@ class StatsReport final {
public:
// METHODS
static void addStat(const V3Statistic& stat) { s_allStats.push_back(stat); }
static void addStat(const V3Statistic& stat) {
// Avoid memory blow-up when called frequently with zero adds,
// e.g. from V3Const invoked on individual expressions.
if (stat.sumit() && stat.value() == 0.0) return;
s_allStats.push_back(stat);
}
static double getStatSum(const string& name) {
// O(n^2) if called a lot; present assumption is only a small call count