Mark Santaniello
Performance & Capacity Engineer at Meta
Redmond, Washington, United States
Summary
🤩
Rockstar🎓
Top SchoolMark Santaniello is a Performance & Capacity Engineer with 20+ years of low-level systems and C++ expertise, currently driving large-scale efficiency at Meta where his compiler, allocator, and profiling work saved hundreds of millions in CapEx and unlocked significant revenue gains. A career systems programmer who consistently works "close to the metal," he blends deep knowledge of CPU architecture, compilers, assembly, and memory management with practical networking, codec, and encryption experience. At Meta he led a company-wide GCC-to-Clang migration, deployed FDO/LTO and site-wide profiling infrastructure, and ran cross-functional performance syncs that coordinated dozens of teams. His open-source contributions to high-profile projects like Facebook's Thrift and Folly show allocator-aware C++ design and pragmatic improvements to memory and compiler interactions. Previously at Microsoft and AMD he diagnosed and fixed critical storage, NUMA/DIMM, and compiler codegen issues that delivered multi-million-dollar system wins. Known for mentoring engineers and founding Meta’s Seattle team, he pairs rare hardware-awareness with production-grade software delivery.
11 years of coding experience
14 years of employment as a software developer
Bachelor of Science Computer Science, Bachelor of Science Computer Science at Rochester Institute of Technology
Github Skills (34)
algorithm10
unit-testing10
algorithms10
c-language10
preprocessing10
preprocess10
memory-management10
hacking10
c-preprocessor10
html-template10
python-templates10
hhvm10
data-structure10
chef-client10
code-templates10
Programming languages (4)
Github contributions (5)
facebook/folly
May 2016 - Mar 2022
An open-source C++ library developed and used at Facebook.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:25 commits, 1 PR in 5 years 10 months
Contributions summary:Mark primarily focused on enhancing the folly library, a C++ library used at Facebook. Their contributions involved addressing compiler warnings, such as those related to boolean comparisons and sign comparisons, by implementing preprocessor directives. They also worked on improving the library's memory management by const-qualifying data members, adding support for PMR (polymorphic memory resources), and incorporating sized deallocation in `SysAllocator` and `Arena`. Further work included adding a `clear()` API, and making the `small_vector` move assignment noexcept.
facebookcppc-library
facebook/fbthrift
Apr 2020 - Jul 2022
Facebook's branch of Apache Thrift, including a new C++ server.
Role in this project:Back-end Developer
Back-end DeveloperContributions:24 commits in 2 years 3 months
Contributions summary:Mark primarily focused on enhancing the C++ side of the Facebook Thrift project, specifically concerning allocator awareness and memory management within the generated C++ code. Their contributions included implementing new annotations for allocator-aware structs, adding `get_allocator()` methods, and ensuring allocators are correctly propagated during deserialization. They also addressed bugs related to allocator usage with sorted unique constructible map/set, and improved unit tests.
cppapache-thriftc-plus-plusapachefacebook
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