Calle Wilund
Senior Software Engineer at ScyllaDB
Greater Stockholm Metropolitan Area Sweden
Summary
🤩
Rockstar🎓
Top SchoolCalle Wilund is a senior software engineer and co-founder of Appeal Virtual Machines with 12 years of experience building high-performance runtimes and systems-level software. He was a primary architect and developer of the JRockit Java VM and later led runtime work at Oracle, giving him rare deep expertise across VM internals, compilers, and JVM tooling. Today he focuses on machine-near C++ distributed database work at ScyllaDB while running an independent software company that produced a commercial audio sampler, showing both low-level systems skill and product-building chops. His open-source contributions include tracing and Java integration work on the cloud-focused OSv project and performance/monitoring improvements to Seastar’s scolectd, reflecting a practical bent for observability and high-throughput servers. Comfortable from assembly to enterprise Java, he blends relentless performance tuning with principled OO architecture. Based in the Stockholm area, he brings an unusual combination of VM originator pedigree and hands-on production engineering for latency-sensitive systems.
12 years of coding experience
13 years of employment as a software developer
Masters, Computer science, Masters, Computer science at Royal Institute of Technology
English, Swedish
Github Skills (22)
asynchronous10
debugging10
debug10
c-language10
system-programming10
tracer10
async10
collectd10
networking10
seastar10
performance-optimization10
cprogramming-language10
trace10
operating-system10
jvm9
Programming languages (4)
Github contributions (5)
scylladb/seastar
Oct 2014 - May 2015
High performance server-side application framework
Role in this project:
Back-end & DevOps Engineer
Back-end & DevOps EngineerContributions:98 reviews, 25 commits, 20 PRs in 6 months
Contributions summary:Calle primarily focused on enhancing the `scollectd` module, a component for collecting and sending metrics. Their contributions include refactoring the `scollectd` module to use well-known types for improved compatibility with the collectd server and optimizing the protocol writer to reduce overhead. Furthermore, they added several counters for monitoring reactor and added packet filtering functionality and related accessors. The user's work demonstrates expertise in server-side application development and systems monitoring within the context of a high-performance server framework.
seastarc-plus-plusdpdkframeworkperformance
cloudius-systems/osv
Apr 2014 - Oct 2014
OSv, a new operating system for the cloud.
Role in this project:Back-end Developer
Back-end DeveloperContributions:34 commits in 5 months
Contributions summary:Calle primarily contributed to the OSv operating system's tracing and debugging infrastructure. They implemented per-CPU trace buffers and event terminators, improving the efficiency and accuracy of trace data extraction. Additionally, they modified the REST API by adding functionality to support trace dump extraction, indicating contributions to the system's management and analysis capabilities. They also worked on the java integration, making changes to the java startup as well as the jvmti.
operating-systemoperatinglinuxosv
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