================
@@ -471,6 +471,66 @@ ProfileGenerator::getTopLevelFunctionProfile(FunctionId
FuncName) {
return ProfileMap.Create(Context);
}
+// Use a heuristic to determine probe order by checking callsite insertion
+// position relative to the BB probes. Sort all the BB probes is in a list, for
+// each calliste, compute "ratio = insert position / length of the list". For
+// the old order, the probe ids for BB should be all before(smaller than) the
+// probe ids for callsite, this ratio should be equal to or close to 1.
+bool checkProbeIDIsInMixedOrder(const SampleProfileMap &Profiles) {
+ // Use flattned profile to maximize the callsites in the profile.
+ SampleProfileMap flattenProfile;
+ ProfileConverter::flattenProfile(Profiles, flattenProfile);
+
+ uint32_t PossibleOldOrderNum = 0;
+ uint32_t PossibleNewOrderNum = 0;
+
+ for (const auto &I : flattenProfile) {
+ const FunctionSamples &FS = I.second;
+ // Skip small functions whose profile order are likely random.
+ if (FS.getBodySamples().size() < 10)
+ continue;
+
+ std::set<uint32_t> PossibleBBProbeIDs;
+ std::set<uint32_t> CallsiteIDs;
+ for (const auto &I : FS.getBodySamples()) {
+ if (I.second.getCallTargets().empty())
+ PossibleBBProbeIDs.insert(I.first.LineOffset);
+ else
+ CallsiteIDs.insert(I.first.LineOffset);
+ }
+
+ if (PossibleBBProbeIDs.empty() || CallsiteIDs.empty())
+ continue;
+
+ uint32_t DistanceToBeginSum = 0;
+ for (const auto &ID : CallsiteIDs)
+ DistanceToBeginSum += std::distance(PossibleBBProbeIDs.begin(),
+ PossibleBBProbeIDs.upper_bound(ID));
+ uint32_t LengthSum = PossibleBBProbeIDs.size() * CallsiteIDs.size();
+
+ // Note that PossibleBBProbeIDs could contains some callsite probe id, the
+ // ratio is not exactly 1 for the old order, hence use a smaller threshold
+ // to determine.
+ if ((float)DistanceToBeginSum / LengthSum > 0.8)
+ PossibleOldOrderNum++;
+ else
+ PossibleNewOrderNum++;
+ }
+ return PossibleNewOrderNum >= PossibleOldOrderNum;
----------------
WenleiHe wrote:
This seems quite fuzzy.. If we can't decide whether a probe is originally a
call probe or a block probe, that makes the checking less reliable.. I wasn't
anticipating that, but if that's case we can't even confidently issue error.
In reality, do we see cases where there are many `PossibleNewOrderNum` and
`PossibleOldOrderNum` for one profile?
https://github.com/llvm/llvm-project/pull/75092
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