gramineproject
Page Cache support for trusted files
Description of the changes
Please check issue #1712 for details.
This PR introduces a manifest option sgx.tf_max_chunks_in_cache which specifies the sub-region of each trusted file is cached if the file is opened more than 10 times. Cache eviction policy is Least Recently Used aka LRU. This optimization is used when there are frequently-reused files.
Downside of this optimization: If the files are rarely reused, then this optimization unnecessarily fills out enclave memory. and if there are too many files, then too much memory will be spent on the cache.
Below are the results with and without this PR for nginx run:
| Marit | Threads | Native | SGX (without page cache) | SGX (with page cache) | Degradation without page cache | Degradation with page cache |
|---|---|---|---|---|---|---|
| Requests/sec | 64 | 930275 | 29030 | 817008 | 97% | 12% |
Fixes #1712
How to test this PR?
Change worker_processes value to auto in CI-Examples/nginx/nginx-gramine.conf.template
Add open_file_cache max=1024 inactive=10s; under http { block in CI-Examples/nginx/nginx-gramine.conf.template
cd gramine/CI-Examples/nginx
make clean && make SGX=1
Native run:
./install/sbin/nginx -c conf/nginx-gramine.conf
wrk -t64 -c300 -d30s http://127.0.0.1:8002/random/10K.1.html
SGX run:
gramine-sgx nginx
wrk -t64 -c300 -d30s http://127.0.0.1:8002/random/10K.1.html
Initial 1-3 run with gramine-sgx might give low performance results as trusted file chuks are added to the page cache for the first time. After 1-3 iterations results become consistent.
This change is 
