EE Seminar: Regaining Lost Cycles with HotCalls: A Fast Interface for SGX Secure Enclaves
(The talk will be given in English)
Speaker: Ofir Weisse
PhD student at the University of Michigan, USA
Wednesday, January 3rd, 2018
15:00 - 16:00
Room 011, Kitot Bldg., Faculty of Engineering
Regaining Lost Cycles with HotCalls: A Fast Interface for SGX Secure Enclaves
Abstract
Intel's SGX secure execution technology allows the running of computations on secret data using untrusted cloud servers. While recent work showed how to port applications and large scale computations to run under SGX, the performance implications of using the technology remains an open question. We present the first comprehensive quantitative study to evaluate the performance of SGX. We show that straightforward use of SGX library primitives for calling functions add between 8,200 - 17,000 cycles overhead, compared to 150 cycles of a typical system call. We quantify the performance impact of these library calls and show that in applications with high system calls frequency, such as memcached, openVPN, and lighttpd, which all have high bandwidth network requirements, the performance degradation may be as high as 79%. We investigate the sources of this performance degradation by leveraging a new set of micro-benchmarks for SGX-specific operations such as entry-calls and out-calls, and encrypted memory I/O accesses. We leverage the insights we gain from these analyses to design a new SGX interface framework, HotCalls: HotCalls provide a 13-27x speedup over the default interface. It can easily be integrated into existing code, making it a practical solution. Compared to a baseline SGX implementation of memcached, openVPN, and lighttpd - we show that using the new interface boosts the throughput by 2.6-3.7x, and reduce application response time by 62-74%.
