Cache JNI jClass jfieldID lookups #314
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@smirnoal can you take a look at this? |
carlzogh
approved these changes
Aug 10, 2022
smirnoal
reviewed
Aug 10, 2022
| CHECK_EXCEPTION(env, env->SetLongField(invocationRequest, deadlineTimeInMsField, std::chrono::duration_cast<std::chrono::milliseconds>(response.deadline.time_since_epoch()).count())); | ||
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| if(response.xray_trace_id != ""){ | ||
| CHECK_EXCEPTION(env, xrayTraceIdField = env->GetFieldID(invocationRequestClass , "xrayTraceId", "Ljava/lang/String;")); | ||
| if(xrayTraceIdField == nullptr){ |
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why are these conditions needed for xrayTraceIdField, clientContextField, cognitoIdentityField?
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@smirnoal Not all next responses contain them, so it would be more efficient to load them lazily than eagerly. Note that they are still cached once they are loaded.
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I'd move them to JNI_OnLoad to have all the fields initialisation in one place and reduce complexity here a bit. It would be good to know performance implications of this, I'm just assuming they are negligible
smirnoal
approved these changes
Aug 15, 2022
smirnoal
approved these changes
Aug 16, 2022
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thanks Richard |
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Description of changes:
JNI class/fieldID lookup can be an expensive operation. This PR moves out the class/fieldId lookup outside the next call to minimise the overhead.
More information:
https://developer.android.com/training/articles/perf-jni#jclass,-jmethodid,-and-jfieldid
https://developer.ibm.com/articles/j-jni/#notc
http://normanmaurer.me/blog/2014/01/07/JNI-Performance-Welcome-to-the-dark-side/
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.