Implement NN HAL for compilation caching.

Add three methods
- IDevice::isCachingSupported
- IDevice::prepareModelFromCache
- IPreparedModel::saveToCache

Bug: 119616526
Test: NeuralNetworksTest_static
Test: VtsHalNeuralnetworksV1_xTargetTest with 1.2 sample driver
Change-Id: If28ffe0be48bcb9f4715293fc1201c8d2dbeb946
This commit is contained in:
Xusong Wang 2019-01-11 17:41:11 -08:00
parent 16337343e9
commit 89dfafb42f
3 changed files with 164 additions and 0 deletions

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@ -97,6 +97,25 @@ interface IDevice extends @1.1::IDevice {
getSupportedOperations_1_2(Model model)
generates (ErrorStatus status, vec<bool> supportedOperations);
/**
* Gets whether the driver supports compilation caching.
*
* isCachingSupported indicates whether the driver supports compilation caching.
* Even if so, the driver may still choose not to cache certain compiled models.
*
* If the device reports the caching is not supported, the user may avoid calling
* IDevice::prepareModelFromCache and IPreparedModel::saveToCache.
*
* @return status Error status of the call, must be:
* - NONE if successful
* - DEVICE_UNAVAILABLE if driver is offline or busy
* - GENERAL_FAILURE if there is an unspecified error
* @return supported A boolean indicating whether the driver supports compilation
* caching. Even on returning true, the driver may still choose
* not to cache certain compiled models.
*/
isCachingSupported() generates (ErrorStatus status, bool supported);
/**
* Creates a prepared model for execution.
*
@ -153,4 +172,84 @@ interface IDevice extends @1.1::IDevice {
prepareModel_1_2(Model model, ExecutionPreference preference,
IPreparedModelCallback callback)
generates (ErrorStatus status);
/**
* Creates a prepared model from cache files for execution.
*
* prepareModelFromCache is used to retrieve a prepared model directly from
* cache files to avoid slow model compilation time. There are exactly two
* cache file descriptors provided to the driver: modelCache and dataCache.
*
* The dataCache is for caching constant data, possibly including preprocessed
* and transformed tensor buffers. Any modification to the dataCache should
* have no worse effect than generating bad output values at execution time.
*
* The modelCache is for caching security-sensitive data such as compiled
* executable machine code in the device's native binary format. A modification
* to the modelCache may affect the driver's execution behavior, and a malicious
* client could make use of this to execute beyond the granted permission. Thus,
* the driver must always check whether the modelCache is corrupted before preparing
* the model from cache.
*
* The two file descriptors may be closed by the client once the asynchronous
* preparation has finished. The driver has to copy all the data it needs.
*
* The model is prepared asynchronously with respect to the caller. The
* prepareModelFromCache function must verify the inputs to the
* prepareModelFromCache function are correct, and that the security-sensitive
* cache has not been modified since it was last written by the driver.
* If there is an error, or if compilation caching is not supported, or if the
* security-sensitive cache has been modified, prepareModelFromCache must
* immediately invoke the callback with the appropriate ErrorStatus value and
* nullptr for the IPreparedModel, then return with the same ErrorStatus. If
* the inputs to the prepareModelFromCache function are valid, the security-sensitive
* cache is not modified, and there is no error, prepareModelFromCache must launch an
* asynchronous task to prepare the model in the background, and immediately return
* from prepareModelFromCache with ErrorStatus::NONE. If the asynchronous task
* fails to launch, prepareModelFromCache must immediately invoke the callback
* with ErrorStatus::GENERAL_FAILURE and nullptr for the IPreparedModel, then
* return with ErrorStatus::GENERAL_FAILURE.
*
* When the asynchronous task has finished preparing the model, it must
* immediately invoke the callback function provided as an input to
* prepareModelFromCache. If the model was prepared successfully, the
* callback object must be invoked with an error status of ErrorStatus::NONE
* and the produced IPreparedModel object. If an error occurred preparing
* the model, the callback object must be invoked with the appropriate
* ErrorStatus value and nullptr for the IPreparedModel.
*
* The only information that may be unknown to the model at this stage is
* the shape of the tensors, which may only be known at execution time. As
* such, some driver services may return partially prepared models, where
* the prepared model may only be finished when it is paired with a set of
* inputs to the model. Note that the same prepared model object may be
* used with different shapes of inputs on different (possibly concurrent)
* executions.
*
* @param modelCache A handle holding exactly one cache file descriptor for the
* security-sensitive cache.
* @param dataCache A handle holding exactly one cache file descriptor for the
* constants' cache.
* @param token A caching token of length Constant::BYTE_SIZE_OF_CACHE_TOKEN
* identifying the prepared model. It is the same token provided when saving
* the cache files with IPreparedModel::saveToCache. Tokens should be chosen
* to have a low rate of collision for a particular application. The driver
* cannot detect a collision; a collision will result in a failed execution
* or in a successful execution that produces incorrect output values.
* @param callback A callback object used to return the error status of
* preparing the model for execution and the prepared model if
* successful, nullptr otherwise. The callback object's notify function
* must be called exactly once, even if the model could not be prepared.
* @return status Error status of launching a task which prepares the model
* in the background; must be:
* - NONE if preparation task is successfully launched
* - DEVICE_UNAVAILABLE if driver is offline or busy
* - GENERAL_FAILURE if caching is not supported or if there is an
* unspecified error
* - INVALID_ARGUMENT if one of the input arguments is invalid
*/
prepareModelFromCache(handle modelCache, handle dataCache,
uint8_t[Constant:BYTE_SIZE_OF_CACHE_TOKEN] token,
IPreparedModelCallback callback)
generates (ErrorStatus status);
};

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@ -157,4 +157,62 @@ interface IPreparedModel extends @1.0::IPreparedModel {
fmq_sync<FmqRequestDatum> requestChannel,
fmq_sync<FmqResultDatum> resultChannel)
generates (ErrorStatus status, IBurstContext context);
/*
* Saves the prepared model to cache files.
*
* saveToCache is used to save a prepared model to cache files for faster
* model compilation time when the same model preparation is requested in
* the future. There are exactly two cache file descriptors provided to the
* driver: modelCache and dataCache.
*
* The dataCache is for caching constant data, possibly including preprocessed
* and transformed tensor buffers. Any modification to the dataCache should
* have no worse effect than generating bad output values at execution time.
*
* The modelCache is for caching security-sensitive data such as compiled
* executable machine code in the device's native binary format. A modification
* to the modelCache may affect the driver's execution behavior, and a malicious
* client could make use of this to execute beyond the granted permission. Thus,
* the driver must always check whether the modelCache is corrupted before preparing
* the model from cache.
*
* The two file descriptors must point to two zero-length files with offset
* positioned at the beginning of the file. The file descriptors may be closed
* by the client once the method has returned.
*
* If the driver decides not to save the prepared model without looking at the
* input arguments to the saveToCache function, saveToCache must return with
* ErrorStatus::GENERAL_FAILURE. Otherwise, the saveToCache function must verify
* the input arguments to the saveToCache function are valid, and return with
* ErrorStatus::INVALID_ARGUMENT if not. If the inputs are valid but the driver
* could not save the prepared model, saveToCache must return with the appropriate
* ErrorStatus. Otherwise, it must write the cache files and return
* ErrorStatus::NONE. Unless saveToCache returns ErrorStatus::NONE, the contents
* of the cache files are undefined.
*
* @param modelCache A handle holding exactly one cache file descriptor for the
* security-sensitive cache.
* @param dataCache A handle holding exactly one cache file descriptor for the
* constants' cache.
* @param token A caching token of length Constant::BYTE_SIZE_OF_CACHE_TOKEN
* identifying the prepared model. The same token will be provided
* when retrieving the prepared model from cache files with
* IDevice::prepareModelFromCache. Tokens should be chosen to have
* a low rate of collision for a particular application. The driver
* cannot detect a collision; a collision will result in a failed
* execution or in a successful execution that produces incorrect
* output values.
* @return status Error status of saveToCache, must be:
* - NONE if saveToCache is performed successfully
* - DEVICE_UNAVAILABLE if driver is offline or busy
* - GENERAL_FAILURE if the driver could not save the
* prepared model or if there is an unspecified error
* - INVALID_ARGUMENT if one of the input arguments is invalid,
* unless the driver decides not to save the prepared model
* without looking at the input arguments
*/
saveToCache(handle modelCache, handle dataCache,
uint8_t[Constant:BYTE_SIZE_OF_CACHE_TOKEN] token)
generates (ErrorStatus status);
};

View file

@ -25,6 +25,13 @@ import @1.1::OperationType;
import android.hidl.safe_union@1.0::Monostate;
enum Constant : uint32_t {
/**
* The byte size of the cache token.
*/
BYTE_SIZE_OF_CACHE_TOKEN = 32,
};
enum OperandType : @1.0::OperandType {
/**
* An 8 bit boolean scalar value.