[llvm] r269222 - [ProfileData] Use SoftInstrProfErrors to count soft errors, NFC

Xinliang David Li via llvm-commits llvm-commits at lists.llvm.org
Thu Jun 29 09:44:51 PDT 2017


The size impact of this struct is indeed pretty large. We can consider
compress the size of it significantly. For instance, making each member
uint8_t.  If the number of errors of each category > 255, it can be capped
at 255 and the error message handling can be adjusted properly.

David

On Wed, Jun 28, 2017 at 11:57 PM, David Blaikie <dblaikie at gmail.com> wrote:

> This seems to have gone unused for a year so far - shall we remove it
> until there's an actual use case?
>
> I came across this because the sizeof(InstrProfRecord) contributes
> significantly to the memory footprint of llvm-profdata merge (I've made one
> big improvement so far (14GB -> 10GB for an example large profile)). I have
> a change in mind/prototyped that helps that (10GB -> 5GB) by moving the
> counters into a sub-struct of InstrProfRecord and using only that
> sub-struct in the InstrProfWriter (since it has the name and hash in the
> maps its using for lookup during merging - so they don't need to be
> duplicated in the values too). But this SoftInstrProfErrors is used from
> the counter-related functions and is quite large, so naively it would have
> to move into this sub-struct & take up lots of space.
>
> So at the very least I'd like to revisit the choice to make this a member,
> and instead go with the earlier version of this patch that wired it through
> function parameters instead - but given the lack of use, I think maybe it'd
> be better to remove this unused abstraction & go back to the simpler error
> handling that was present before.
>
> - Dave
>
> On Wed, May 11, 2016 at 12:48 PM Vedant Kumar via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> Author: vedantk
>> Date: Wed May 11 14:42:19 2016
>> New Revision: 269222
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=269222&view=rev
>> Log:
>> [ProfileData] Use SoftInstrProfErrors to count soft errors, NFC
>>
>> Differential Revision: http://reviews.llvm.org/D20082
>>
>> Modified:
>>     llvm/trunk/include/llvm/ProfileData/InstrProf.h
>>     llvm/trunk/lib/ProfileData/InstrProf.cpp
>>     llvm/trunk/lib/ProfileData/InstrProfWriter.cpp
>>
>> Modified: llvm/trunk/include/llvm/ProfileData/InstrProf.h
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/
>> llvm/ProfileData/InstrProf.h?rev=269222&r1=269221&r2=269222&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/include/llvm/ProfileData/InstrProf.h (original)
>> +++ llvm/trunk/include/llvm/ProfileData/InstrProf.h Wed May 11 14:42:19
>> 2016
>> @@ -284,15 +284,51 @@ inline std::error_code make_error_code(i
>>    return std::error_code(static_cast<int>(E), instrprof_category());
>>  }
>>
>> -inline instrprof_error MergeResult(instrprof_error &Accumulator,
>> -                                   instrprof_error Result) {
>> -  // Prefer first error encountered as later errors may be secondary
>> effects of
>> -  // the initial problem.
>> -  if (Accumulator == instrprof_error::success &&
>> -      Result != instrprof_error::success)
>> -    Accumulator = Result;
>> -  return Accumulator;
>> -}
>> +class SoftInstrProfErrors {
>> +  /// Count the number of soft instrprof_errors encountered and keep
>> track of
>> +  /// the first such error for reporting purposes.
>> +
>> +  /// The first soft error encountered.
>> +  instrprof_error FirstError;
>> +
>> +  /// The number of hash mismatches.
>> +  unsigned NumHashMismatches;
>> +
>> +  /// The number of count mismatches.
>> +  unsigned NumCountMismatches;
>> +
>> +  /// The number of counter overflows.
>> +  unsigned NumCounterOverflows;
>> +
>> +  /// The number of value site count mismatches.
>> +  unsigned NumValueSiteCountMismatches;
>> +
>> +public:
>> +  SoftInstrProfErrors()
>> +      : FirstError(instrprof_error::success), NumHashMismatches(0),
>> +        NumCountMismatches(0), NumCounterOverflows(0),
>> +        NumValueSiteCountMismatches(0) {}
>> +
>> +  /// Track a soft error (\p IE) and increment its associated counter.
>> +  void addError(instrprof_error IE);
>> +
>> +  /// Get the number of hash mismatches.
>> +  unsigned getNumHashMismatches() const { return NumHashMismatches; }
>> +
>> +  /// Get the number of count mismatches.
>> +  unsigned getNumCountMismatches() const { return NumCountMismatches; }
>> +
>> +  /// Get the number of counter overflows.
>> +  unsigned getNumCounterOverflows() const { return NumCounterOverflows; }
>> +
>> +  /// Get the number of value site count mismatches.
>> +  unsigned getNumValueSiteCountMismatches() const {
>> +    return NumValueSiteCountMismatches;
>> +  }
>> +
>> +  /// Return an error code for the first encountered error.
>> +  std::error_code getError() const { return make_error_code(FirstError);
>> }
>> +};
>>
>>  namespace object {
>>  class SectionRef;
>> @@ -465,19 +501,21 @@ struct InstrProfValueSiteRecord {
>>
>>    /// Merge data from another InstrProfValueSiteRecord
>>    /// Optionally scale merged counts by \p Weight.
>> -  instrprof_error merge(InstrProfValueSiteRecord &Input, uint64_t Weight
>> = 1);
>> +  void merge(SoftInstrProfErrors &SIPE, InstrProfValueSiteRecord &Input,
>> +             uint64_t Weight = 1);
>>    /// Scale up value profile data counts.
>> -  instrprof_error scale(uint64_t Weight);
>> +  void scale(SoftInstrProfErrors &SIPE, uint64_t Weight);
>>  };
>>
>>  /// Profiling information for a single function.
>>  struct InstrProfRecord {
>> -  InstrProfRecord() {}
>> +  InstrProfRecord() : SIPE() {}
>>    InstrProfRecord(StringRef Name, uint64_t Hash, std::vector<uint64_t>
>> Counts)
>> -      : Name(Name), Hash(Hash), Counts(std::move(Counts)) {}
>> +      : Name(Name), Hash(Hash), Counts(std::move(Counts)), SIPE() {}
>>    StringRef Name;
>>    uint64_t Hash;
>>    std::vector<uint64_t> Counts;
>> +  SoftInstrProfErrors SIPE;
>>
>>    typedef std::vector<std::pair<uint64_t, uint64_t>> ValueMapType;
>>
>> @@ -512,11 +550,11 @@ struct InstrProfRecord {
>>
>>    /// Merge the counts in \p Other into this one.
>>    /// Optionally scale merged counts by \p Weight.
>> -  instrprof_error merge(InstrProfRecord &Other, uint64_t Weight = 1);
>> +  void merge(InstrProfRecord &Other, uint64_t Weight = 1);
>>
>>    /// Scale up profile counts (including value profile data) by
>>    /// \p Weight.
>> -  instrprof_error scale(uint64_t Weight);
>> +  void scale(uint64_t Weight);
>>
>>    /// Sort value profile data (per site) by count.
>>    void sortValueData() {
>> @@ -533,6 +571,9 @@ struct InstrProfRecord {
>>        getValueSitesForKind(Kind).clear();
>>    }
>>
>> +  /// Get the error contained within the record's soft error counter.
>> +  std::error_code getError() const { return SIPE.getError(); }
>> +
>>  private:
>>    std::vector<InstrProfValueSiteRecord> IndirectCallSites;
>>    const std::vector<InstrProfValueSiteRecord> &
>> @@ -559,10 +600,10 @@ private:
>>
>>    // Merge Value Profile data from Src record to this record for
>> ValueKind.
>>    // Scale merged value counts by \p Weight.
>> -  instrprof_error mergeValueProfData(uint32_t ValueKind, InstrProfRecord
>> &Src,
>> -                                     uint64_t Weight);
>> +  void mergeValueProfData(uint32_t ValueKind, InstrProfRecord &Src,
>> +                          uint64_t Weight);
>>    // Scale up value profile data count.
>> -  instrprof_error scaleValueProfData(uint32_t ValueKind, uint64_t
>> Weight);
>> +  void scaleValueProfData(uint32_t ValueKind, uint64_t Weight);
>>  };
>>
>>  uint32_t InstrProfRecord::getNumValueKinds() const {
>>
>> Modified: llvm/trunk/lib/ProfileData/InstrProf.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
>> ProfileData/InstrProf.cpp?rev=269222&r1=269221&r2=269222&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/lib/ProfileData/InstrProf.cpp (original)
>> +++ llvm/trunk/lib/ProfileData/InstrProf.cpp Wed May 11 14:42:19 2016
>> @@ -80,6 +80,31 @@ const std::error_category &llvm::instrpr
>>
>>  namespace llvm {
>>
>> +void SoftInstrProfErrors::addError(instrprof_error IE) {
>> +  if (IE == instrprof_error::success)
>> +    return;
>> +
>> +  if (FirstError == instrprof_error::success)
>> +    FirstError = IE;
>> +
>> +  switch (IE) {
>> +  case instrprof_error::hash_mismatch:
>> +    ++NumHashMismatches;
>> +    break;
>> +  case instrprof_error::count_mismatch:
>> +    ++NumCountMismatches;
>> +    break;
>> +  case instrprof_error::counter_overflow:
>> +    ++NumCounterOverflows;
>> +    break;
>> +  case instrprof_error::value_site_count_mismatch:
>> +    ++NumValueSiteCountMismatches;
>> +    break;
>> +  default:
>> +    llvm_unreachable("Not a soft error");
>> +  }
>> +}
>> +
>>  std::string getPGOFuncName(StringRef RawFuncName,
>>                             GlobalValue::LinkageTypes Linkage,
>>                             StringRef FileName,
>> @@ -291,13 +316,13 @@ std::error_code readPGOFuncNameStrings(S
>>    return make_error_code(instrprof_error::success);
>>  }
>>
>> -instrprof_error InstrProfValueSiteRecord::merge(InstrProfValueSiteRecord
>> &Input,
>> -                                                uint64_t Weight) {
>> +void InstrProfValueSiteRecord::merge(SoftInstrProfErrors &SIPE,
>> +                                     InstrProfValueSiteRecord &Input,
>> +                                     uint64_t Weight) {
>>    this->sortByTargetValues();
>>    Input.sortByTargetValues();
>>    auto I = ValueData.begin();
>>    auto IE = ValueData.end();
>> -  instrprof_error Result = instrprof_error::success;
>>    for (auto J = Input.ValueData.begin(), JE = Input.ValueData.end(); J
>> != JE;
>>         ++J) {
>>      while (I != IE && I->Value < J->Value)
>> @@ -306,92 +331,80 @@ instrprof_error InstrProfValueSiteRecord
>>        bool Overflowed;
>>        I->Count = SaturatingMultiplyAdd(J->Count, Weight, I->Count,
>> &Overflowed);
>>        if (Overflowed)
>> -        Result = instrprof_error::counter_overflow;
>> +        SIPE.addError(instrprof_error::counter_overflow);
>>        ++I;
>>        continue;
>>      }
>>      ValueData.insert(I, *J);
>>    }
>> -  return Result;
>>  }
>>
>> -instrprof_error InstrProfValueSiteRecord::scale(uint64_t Weight) {
>> -  instrprof_error Result = instrprof_error::success;
>> +void InstrProfValueSiteRecord::scale(SoftInstrProfErrors &SIPE,
>> +                                     uint64_t Weight) {
>>    for (auto I = ValueData.begin(), IE = ValueData.end(); I != IE; ++I) {
>>      bool Overflowed;
>>      I->Count = SaturatingMultiply(I->Count, Weight, &Overflowed);
>>      if (Overflowed)
>> -      Result = instrprof_error::counter_overflow;
>> +      SIPE.addError(instrprof_error::counter_overflow);
>>    }
>> -  return Result;
>>  }
>>
>>  // Merge Value Profile data from Src record to this record for ValueKind.
>>  // Scale merged value counts by \p Weight.
>> -instrprof_error InstrProfRecord::mergeValueProfData(uint32_t ValueKind,
>> -                                                    InstrProfRecord &Src,
>> -                                                    uint64_t Weight) {
>> +void InstrProfRecord::mergeValueProfData(uint32_t ValueKind,
>> +                                         InstrProfRecord &Src,
>> +                                         uint64_t Weight) {
>>    uint32_t ThisNumValueSites = getNumValueSites(ValueKind);
>>    uint32_t OtherNumValueSites = Src.getNumValueSites(ValueKind);
>> -  if (ThisNumValueSites != OtherNumValueSites)
>> -    return instrprof_error::value_site_count_mismatch;
>> +  if (ThisNumValueSites != OtherNumValueSites) {
>> +    SIPE.addError(instrprof_error::value_site_count_mismatch);
>> +    return;
>> +  }
>>    std::vector<InstrProfValueSiteRecord> &ThisSiteRecords =
>>        getValueSitesForKind(ValueKind);
>>    std::vector<InstrProfValueSiteRecord> &OtherSiteRecords =
>>        Src.getValueSitesForKind(ValueKind);
>> -  instrprof_error Result = instrprof_error::success;
>>    for (uint32_t I = 0; I < ThisNumValueSites; I++)
>> -    MergeResult(Result, ThisSiteRecords[I].merge(OtherSiteRecords[I],
>> Weight));
>> -  return Result;
>> +    ThisSiteRecords[I].merge(SIPE, OtherSiteRecords[I], Weight);
>>  }
>>
>> -instrprof_error InstrProfRecord::merge(InstrProfRecord &Other,
>> -                                       uint64_t Weight) {
>> +void InstrProfRecord::merge(InstrProfRecord &Other, uint64_t Weight) {
>>    // If the number of counters doesn't match we either have bad data
>>    // or a hash collision.
>> -  if (Counts.size() != Other.Counts.size())
>> -    return instrprof_error::count_mismatch;
>> -
>> -  instrprof_error Result = instrprof_error::success;
>> +  if (Counts.size() != Other.Counts.size()) {
>> +    SIPE.addError(instrprof_error::count_mismatch);
>> +    return;
>> +  }
>>
>>    for (size_t I = 0, E = Other.Counts.size(); I < E; ++I) {
>>      bool Overflowed;
>>      Counts[I] =
>>          SaturatingMultiplyAdd(Other.Counts[I], Weight, Counts[I],
>> &Overflowed);
>>      if (Overflowed)
>> -      Result = instrprof_error::counter_overflow;
>> +      SIPE.addError(instrprof_error::counter_overflow);
>>    }
>>
>>    for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
>> -    MergeResult(Result, mergeValueProfData(Kind, Other, Weight));
>> -
>> -  return Result;
>> +    mergeValueProfData(Kind, Other, Weight);
>>  }
>>
>> -instrprof_error InstrProfRecord::scaleValueProfData(uint32_t ValueKind,
>> -                                                    uint64_t Weight) {
>> +void InstrProfRecord::scaleValueProfData(uint32_t ValueKind, uint64_t
>> Weight) {
>>    uint32_t ThisNumValueSites = getNumValueSites(ValueKind);
>>    std::vector<InstrProfValueSiteRecord> &ThisSiteRecords =
>>        getValueSitesForKind(ValueKind);
>> -  instrprof_error Result = instrprof_error::success;
>>    for (uint32_t I = 0; I < ThisNumValueSites; I++)
>> -    MergeResult(Result, ThisSiteRecords[I].scale(Weight));
>> -  return Result;
>> +    ThisSiteRecords[I].scale(SIPE, Weight);
>>  }
>>
>> -instrprof_error InstrProfRecord::scale(uint64_t Weight) {
>> -  instrprof_error Result = instrprof_error::success;
>> +void InstrProfRecord::scale(uint64_t Weight) {
>>    for (auto &Count : this->Counts) {
>>      bool Overflowed;
>>      Count = SaturatingMultiply(Count, Weight, &Overflowed);
>> -    if (Overflowed && Result == instrprof_error::success) {
>> -      Result = instrprof_error::counter_overflow;
>> -    }
>> +    if (Overflowed)
>> +      SIPE.addError(instrprof_error::counter_overflow);
>>    }
>>    for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
>> -    MergeResult(Result, scaleValueProfData(Kind, Weight));
>> -
>> -  return Result;
>> +    scaleValueProfData(Kind, Weight);
>>  }
>>
>>  // Map indirect call target name hash to name string.
>>
>> Modified: llvm/trunk/lib/ProfileData/InstrProfWriter.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
>> ProfileData/InstrProfWriter.cpp?rev=269222&r1=269221&r2=269222&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/lib/ProfileData/InstrProfWriter.cpp (original)
>> +++ llvm/trunk/lib/ProfileData/InstrProfWriter.cpp Wed May 11 14:42:19
>> 2016
>> @@ -166,22 +166,21 @@ std::error_code InstrProfWriter::addReco
>>        ProfileDataMap.insert(std::make_pair(I.Hash, InstrProfRecord()));
>>    InstrProfRecord &Dest = Where->second;
>>
>> -  instrprof_error Result = instrprof_error::success;
>>    if (NewFunc) {
>>      // We've never seen a function with this name and hash, add it.
>>      Dest = std::move(I);
>>      // Fix up the name to avoid dangling reference.
>>      Dest.Name = FunctionData.find(Dest.Name)->getKey();
>>      if (Weight > 1)
>> -      Result = Dest.scale(Weight);
>> +      Dest.scale(Weight);
>>    } else {
>>      // We're updating a function we've seen before.
>> -    Result = Dest.merge(I, Weight);
>> +    Dest.merge(I, Weight);
>>    }
>>
>>    Dest.sortValueData();
>>
>> -  return Result;
>> +  return Dest.getError();
>>  }
>>
>>  bool InstrProfWriter::shouldEncodeData(const ProfilingData &PD) {
>>
>>
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