Add lz4hc image compression format
Smaller than lz4 and decompresses at the same speed. Compression is
a bit slower.
Example saves on old FB APK:
Uncompressed: 44748800 bytes
LZ4: 12443648 bytes
LZ4HC: 11055104 bytes
Generating the image slows down by ~1s per 20MB of image due to
slower compression. Decompression is about the same speed but there
should be a slight speedup since less data needs to be read from
flash.
Added test.
Bug: 22858531
Change-Id: Ib2704305b9bec5b0ba3b1e871f59f4eedff330b7
diff --git a/runtime/gc/space/image_space.cc b/runtime/gc/space/image_space.cc
index bc21b33..4ef36a4 100644
--- a/runtime/gc/space/image_space.cc
+++ b/runtime/gc/space/image_space.cc
@@ -1252,7 +1252,8 @@
// Only care about the error message for the last address in addresses. We want to avoid the
// overhead of printing the process maps if we can relocate.
std::string* out_error_msg = (address == addresses.back()) ? &temp_error_msg : nullptr;
- if (image_header->GetStorageMode() == ImageHeader::kStorageModeUncompressed) {
+ const ImageHeader::StorageMode storage_mode = image_header->GetStorageMode();
+ if (storage_mode == ImageHeader::kStorageModeUncompressed) {
map.reset(MemMap::MapFileAtAddress(address,
image_header->GetImageSize(),
PROT_READ | PROT_WRITE,
@@ -1264,6 +1265,12 @@
image_filename,
/*out*/out_error_msg));
} else {
+ if (storage_mode != ImageHeader::kStorageModeLZ4 &&
+ storage_mode != ImageHeader::kStorageModeLZ4HC) {
+ *error_msg = StringPrintf("Invalid storage mode in image header %d",
+ static_cast<int>(storage_mode));
+ return nullptr;
+ }
// Reserve output and decompress into it.
map.reset(MemMap::MapAnonymous(image_location,
address,
@@ -1289,6 +1296,7 @@
}
memcpy(map->Begin(), image_header, sizeof(ImageHeader));
const uint64_t start = NanoTime();
+ // LZ4HC and LZ4 have same internal format, both use LZ4_decompress.
TimingLogger::ScopedTiming timing2("LZ4 decompress image", &logger);
const size_t decompressed_size = LZ4_decompress_safe(
reinterpret_cast<char*>(temp_map->Begin()) + sizeof(ImageHeader),
diff --git a/runtime/image.h b/runtime/image.h
index 146ee00..8e5dbad 100644
--- a/runtime/image.h
+++ b/runtime/image.h
@@ -81,6 +81,7 @@
enum StorageMode : uint32_t {
kStorageModeUncompressed,
kStorageModeLZ4,
+ kStorageModeLZ4HC,
kStorageModeCount, // Number of elements in enum.
};
static constexpr StorageMode kDefaultStorageMode = kStorageModeUncompressed;
diff --git a/runtime/oat_file_manager.cc b/runtime/oat_file_manager.cc
index 18cf81a..ea26d58 100644
--- a/runtime/oat_file_manager.cc
+++ b/runtime/oat_file_manager.cc
@@ -16,6 +16,8 @@
#include "oat_file_manager.h"
+#define ATRACE_TAG ATRACE_TAG_DALVIK
+#include <cutils/trace.h>
#include <memory>
#include <queue>
#include <vector>
@@ -386,13 +388,15 @@
ScopedSuspendAll ssa("Add image space");
runtime->GetHeap()->AddSpace(image_space.get());
}
- added_image_space = true;
- if (runtime->GetClassLinker()->AddImageSpace(image_space.get(),
- h_loader,
- dex_elements,
- dex_location,
- /*out*/&dex_files,
- /*out*/&temp_error_msg)) {
+ ATRACE_BEGIN(StringPrintf("Adding image space for location %s", dex_location).c_str());
+ added_image_space = runtime->GetClassLinker()->AddImageSpace(image_space.get(),
+ h_loader,
+ dex_elements,
+ dex_location,
+ /*out*/&dex_files,
+ /*out*/&temp_error_msg);
+ ATRACE_END();
+ if (added_image_space) {
// Successfully added image space to heap, release the map so that it does not get
// freed.
image_space.release();
@@ -407,7 +411,6 @@
ScopedSuspendAll ssa("Remove image space");
runtime->GetHeap()->RemoveSpace(image_space.get());
}
- added_image_space = false;
// Non-fatal, don't update error_msg.
}
}