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Remove telemetry to find optimal cache entry hash size

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Tag #21.
This commit is contained in:
wolfbeast 2018-09-29 22:56:15 +02:00 • committed by Roy Tam
commit f019ffbb0b
5 changed files with 0 additions and 117 deletions
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75
netwerk/cache2/CacheIndex.cpp
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@ -20,7 +20,6 @@
#include "nsITimer.h"
#include "mozilla/AutoRestore.h"
#include <algorithm>
#include "mozilla/Telemetry.h"
#include "mozilla/Unused.h"
@ -3167,11 +3166,6 @@ CacheIndex::ChangeState(EState aNewState)
return;
}
if ((mState == READING || mState == BUILDING || mState == UPDATING) &&
aNewState == READY) {
ReportHashStats();
}
// Try to evict entries over limit everytime we're leaving state READING,
// BUILDING or UPDATING, but not during shutdown or when removing all
// entries.
@ -3720,75 +3714,6 @@ CacheIndex::SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf)
return mallocSizeOf(gInstance) + SizeOfExcludingThis(mallocSizeOf);
}
namespace {
class HashComparator
{
public:
bool Equals(CacheIndexRecord* a, CacheIndexRecord* b) const {
return memcmp(&a->mHash, &b->mHash, sizeof(SHA1Sum::Hash)) == 0;
}
bool LessThan(CacheIndexRecord* a, CacheIndexRecord* b) const {
return memcmp(&a->mHash, &b->mHash, sizeof(SHA1Sum::Hash)) < 0;
}
};
void
ReportHashSizeMatch(const SHA1Sum::Hash *aHash1, const SHA1Sum::Hash *aHash2)
{
const uint32_t *h1 = reinterpret_cast<const uint32_t *>(aHash1);
const uint32_t *h2 = reinterpret_cast<const uint32_t *>(aHash2);
for (uint32_t i = 0; i < 5; ++i) {
if (h1[i] != h2[i]) {
uint32_t bitsDiff = h1[i] ^ h2[i];
bitsDiff = NetworkEndian::readUint32(&bitsDiff);
// count leading zeros in bitsDiff
static const uint8_t debruijn32[32] =
{ 0, 31, 9, 30, 3, 8, 13, 29, 2, 5, 7, 21, 12, 24, 28, 19,
1, 10, 4, 14, 6, 22, 25, 20, 11, 15, 23, 26, 16, 27, 17, 18};
bitsDiff |= bitsDiff>>1;
bitsDiff |= bitsDiff>>2;
bitsDiff |= bitsDiff>>4;
bitsDiff |= bitsDiff>>8;
bitsDiff |= bitsDiff>>16;
bitsDiff++;
uint8_t hashSizeMatch = debruijn32[bitsDiff*0x076be629>>27] + (i<<5);
return;
}
}
MOZ_ASSERT(false, "Found a collision in the index!");
}
} // namespace
void
CacheIndex::ReportHashStats()
{
// We're gathering the hash stats only once, exclude too small caches.
if (CacheObserver::HashStatsReported() || mFrecencyArray.Length() < 15000) {
return;
}
nsTArray<CacheIndexRecord *> records;
for (auto iter = mFrecencyArray.Iter(); !iter.Done(); iter.Next()) {
records.AppendElement(iter.Get());
}
records.Sort(HashComparator());
for (uint32_t i = 1; i < records.Length(); i++) {
ReportHashSizeMatch(&records[i-1]->mHash, &records[i]->mHash);
}
CacheObserver::SetHashStatsReported();
}
// static
void
CacheIndex::OnAsyncEviction(bool aEvicting)