
Over thirteen months, Jiri Olsa engineered advanced kernel observability and tracing features in the cilium/tetragon repository, focusing on robust event processing, policy management, and cross-platform compatibility. He modernized BPF map handling, expanded USDT and uprobe instrumentation, and refactored core event APIs to streamline integration with Kubernetes. Using C, Go, and eBPF, Jiri delivered automated code generation, improved test infrastructure, and enhanced resource lifecycle management, addressing both performance and reliability. His work included deep kernel integration, build system modernization, and comprehensive documentation, resulting in a maintainable, production-ready codebase that supports scalable, low-risk deployments and developer productivity.

2025-10 performance highlights across two repositories: qualcomm-linux/kernel-topics and cilium/tetragon. In kernel-topics, I delivered reliability and safety improvements to the BPF and uprobes test suite, including correcting gettid usage for older libc in uprobe tests and fixing USDT self-test tracking; addressed a realloc sizing issue in bpf_get_addrs to prevent segmentation faults; and refined the uprobe optimization flow to ensure arch_uprobe_optimize runs immediately after the initial handler. In tetragon, I expanded Kubernetes readiness with ArgSelector index/Args optional, integrated generated changes, added tests for wrong USDT set action, and documented the usdt set action; added advanced uprobe capabilities such as addressing via virtual addresses and symbol+offset, plus support for detecting register changes and override actions; performed substantial refactors and code-generation work around kernel selector/argument selectors and asm handling; and completed build/CI improvements (clang upgrade, removal of confapi). Additionally, I fixed critical sensor-related issues, including tail call program types for kprobe, uprobe, and usdt sensors, and a missing switch break in do_action. These changes increase observability, reliability, Kubernetes integration, and developer velocity, while reducing runtime risk across instrumentation features.
2025-10 performance highlights across two repositories: qualcomm-linux/kernel-topics and cilium/tetragon. In kernel-topics, I delivered reliability and safety improvements to the BPF and uprobes test suite, including correcting gettid usage for older libc in uprobe tests and fixing USDT self-test tracking; addressed a realloc sizing issue in bpf_get_addrs to prevent segmentation faults; and refined the uprobe optimization flow to ensure arch_uprobe_optimize runs immediately after the initial handler. In tetragon, I expanded Kubernetes readiness with ArgSelector index/Args optional, integrated generated changes, added tests for wrong USDT set action, and documented the usdt set action; added advanced uprobe capabilities such as addressing via virtual addresses and symbol+offset, plus support for detecting register changes and override actions; performed substantial refactors and code-generation work around kernel selector/argument selectors and asm handling; and completed build/CI improvements (clang upgrade, removal of confapi). Additionally, I fixed critical sensor-related issues, including tail call program types for kprobe, uprobe, and usdt sensors, and a missing switch break in do_action. These changes increase observability, reliability, Kubernetes integration, and developer velocity, while reducing runtime risk across instrumentation features.
September 2025 performance highlights across cilium/tetragon and qualcomm-linux/kernel-topics. Focused on delivering high-value features, improving runtime observability, and stabilizing the codebase for maintenance and future work. Key outcomes include code generation with change tracking, enhanced USDT event handling and specs, expanded data handling and selector tests, and safer, more robust uprobes/kprobes instrumentation. Also delivered loader offload support, task data resolution, and comprehensive test stabilization by removing deprecated APIs.
September 2025 performance highlights across cilium/tetragon and qualcomm-linux/kernel-topics. Focused on delivering high-value features, improving runtime observability, and stabilizing the codebase for maintenance and future work. Key outcomes include code generation with change tracking, enhanced USDT event handling and specs, expanded data handling and selector tests, and safer, more robust uprobes/kprobes instrumentation. Also delivered loader offload support, task data resolution, and comprehensive test stabilization by removing deprecated APIs.
In August 2025, the tetragon project delivered a robust set of tracing enhancements, expanded test coverage, and stability fixes that improve observability, reliability, and safety of kernel-space instrumentation across supported platforms. The work emphasizes business value through more accurate data collection, stronger validation, and lower risk deployments in production. Key outcomes include: USDT enhancements and tests with selector support, usdt-override test programs, usdt set action workflow, argument handling, offload support, and platform-specific test configuration; Generic type system improvements to strengthen type resolution by adding missing dentry type and localizing generic type maps; Uprobes and kprobe handling enhancements with pinning for uprobe links and tests for resolving kprobe arguments using current source; Tracepoint load format enablement to validate compatibility on kernel 6.1 and bpf-next; and data-driven kprobe events with data and source fields and filtering support. Additionally, targeted fixes improve stability and correctness, including removal of an early break in hasMapsSetup and removal of a leftover argsBTFSet variable.
In August 2025, the tetragon project delivered a robust set of tracing enhancements, expanded test coverage, and stability fixes that improve observability, reliability, and safety of kernel-space instrumentation across supported platforms. The work emphasizes business value through more accurate data collection, stronger validation, and lower risk deployments in production. Key outcomes include: USDT enhancements and tests with selector support, usdt-override test programs, usdt set action workflow, argument handling, offload support, and platform-specific test configuration; Generic type system improvements to strengthen type resolution by adding missing dentry type and localizing generic type maps; Uprobes and kprobe handling enhancements with pinning for uprobe links and tests for resolving kprobe arguments using current source; Tracepoint load format enablement to validate compatibility on kernel 6.1 and bpf-next; and data-driven kprobe events with data and source fields and filtering support. Additionally, targeted fixes improve stability and correctness, including removal of an early break in hasMapsSetup and removal of a leftover argsBTFSet variable.
July 2025 monthly summary for cilium/tetragon: Delivered a set of enhancements that improve observability, kernel compatibility, and developer ergonomics, while addressing a cleanup of legacy references. Major features included follow-children of old processes, expanded config object helpers for multi-kprobe usage, USDT integration with tests and documentation, 6.12 kernel readiness, and improvements to code generation and documentation for the selector arg field. Major bugs fixed include cleanup of a forgotten v6.12 variant leftover. Overall impact: increased runtime observability, smoother onboarding for instrumentation tasks, and better alignment with newer kernel releases. Technologies/skills demonstrated include kernel instrumentation (kprobes, uprobes, tracepoints), USDT support and testing, code generation, doc SAR updates, and codebase refactoring (mbset).
July 2025 monthly summary for cilium/tetragon: Delivered a set of enhancements that improve observability, kernel compatibility, and developer ergonomics, while addressing a cleanup of legacy references. Major features included follow-children of old processes, expanded config object helpers for multi-kprobe usage, USDT integration with tests and documentation, 6.12 kernel readiness, and improvements to code generation and documentation for the selector arg field. Major bugs fixed include cleanup of a forgotten v6.12 variant leftover. Overall impact: increased runtime observability, smoother onboarding for instrumentation tasks, and better alignment with newer kernel releases. Technologies/skills demonstrated include kernel instrumentation (kprobes, uprobes, tracepoints), USDT support and testing, code generation, doc SAR updates, and codebase refactoring (mbset).
June 2025 (2025-06) — The tetragon project delivered API cleanups, stability improvements, and new capabilities that sharpen event processing, policy management, and resource lifecycle. Focused work reduced API friction, increased test coverage, and improved runtime safety, enabling faster policy iteration and more reliable event handling across components.
June 2025 (2025-06) — The tetragon project delivered API cleanups, stability improvements, and new capabilities that sharpen event processing, policy management, and resource lifecycle. Focused work reduced API friction, increased test coverage, and improved runtime safety, enabling faster policy iteration and more reliable event handling across components.
May 2025 monthly summary for developer work across repositories focusing on delivering features, stabilizing APIs, and expanding instrumentation capabilities. Highlights include code generation, enhanced uprore/uprobes offset handling, and improved testing coverage with refactors to support maintainability and performance.
May 2025 monthly summary for developer work across repositories focusing on delivering features, stabilizing APIs, and expanding instrumentation capabilities. Highlights include code generation, enhanced uprore/uprobes offset handling, and improved testing coverage with refactors to support maintainability and performance.
April 2025 monthly summary for cilium/tetragon: Focused on kernel compatibility with RHEL7/3.10, enhanced tracing capabilities (tracepoints and USDT), and strengthened test reliability. Delivered a stable variant of BPF objects for RHEL7, improved namespace handling and reduced noisy warnings, and hardened USDT and tracepoint support for production-grade observability.
April 2025 monthly summary for cilium/tetragon: Focused on kernel compatibility with RHEL7/3.10, enhanced tracing capabilities (tracepoints and USDT), and strengthened test reliability. Delivered a stable variant of BPF objects for RHEL7, improved namespace handling and reduced noisy warnings, and hardened USDT and tracepoint support for production-grade observability.
March 2025 monthly summary for the tetragon and little-vm-helper-images repositories. Highlights span feature work, reliability fixes, and performance/portability improvements that collectively enhance observability, scalability, and developer productivity.
March 2025 monthly summary for the tetragon and little-vm-helper-images repositories. Highlights span feature work, reliability fixes, and performance/portability improvements that collectively enhance observability, scalability, and developer productivity.
February 2025 performance summary for cilium/tetragon: Delivered key telemetry and robustness improvements, including a new GetExecveEntries API with max entries exposed from the BPF map, expanded trace capabilities, and stronger test infrastructure. In addition, multiple stability and correctness fixes were completed, strengthening reliability for production deployments and developer workflows.
February 2025 performance summary for cilium/tetragon: Delivered key telemetry and robustness improvements, including a new GetExecveEntries API with max entries exposed from the BPF map, expanded trace capabilities, and stronger test infrastructure. In addition, multiple stability and correctness fixes were completed, strengthening reliability for production deployments and developer workflows.
Monthly summary for 2025-01 focused on delivering business value through robust feature work, stability improvements, and improved observability for cilium/tetragon. Highlights include expanded executable monitoring capabilities, deeper loader/map integration for richer instrumentation, and build/maintenance improvements across architectures, all aimed at safer, faster, and more auditable deployments.
Monthly summary for 2025-01 focused on delivering business value through robust feature work, stability improvements, and improved observability for cilium/tetragon. Highlights include expanded executable monitoring capabilities, deeper loader/map integration for richer instrumentation, and build/maintenance improvements across architectures, all aimed at safer, faster, and more auditable deployments.
December 2024 performance summary for repository cilium/tetragon focusing on reliability, scalability, and developer experience. The team delivered BPF map handling modernization to simplify interfaces, tightened verifier robustness, and improved maintainability by centralizing maps and generic logic into shared components. In Kubernetes contexts, auto-detection of bpffs mount point and BPF library path reduced setup friction. Build-system improvements reduced friction in BPF-related workflows. UI/UX improvements to terminal output enhanced readability during long runs. A critical stability fix was implemented for loading pinned BPF programs, preventing crashes caused by non-program files during ebpf library changes.
December 2024 performance summary for repository cilium/tetragon focusing on reliability, scalability, and developer experience. The team delivered BPF map handling modernization to simplify interfaces, tightened verifier robustness, and improved maintainability by centralizing maps and generic logic into shared components. In Kubernetes contexts, auto-detection of bpffs mount point and BPF library path reduced setup friction. Build-system improvements reduced friction in BPF-related workflows. UI/UX improvements to terminal output enhanced readability during long runs. A critical stability fix was implemented for loading pinned BPF programs, preventing crashes caused by non-program files during ebpf library changes.
During November 2024, the team delivered a set of stability, performance, and observability improvements across two repositories (cilium/tetragon and netdata/libbpf). Key features include: unconditional pinning of links and unpinning in unloader objects in tetragon; refactoring of unloader naming and related code paths; expanded test coverage and stability efforts (persistent enforcement tests, extra sleep in TestEnforcerMulti, and tests for exec events); symbol instances support in non-kprobe-multi specs with kprobe tests; build and tooling enhancements such as updating the ebpf dependency, enabling LLVM IR object builds, and comprehensive Makefile cleanup for cross-version support; and improved documentation for the BPF Makefile. Major user-facing and developer-impacting bugs fixed include: bugtool tracefs log dump, removal of program.LinkPin field, fixes for kprobe multi-attach and fmodret attach override link paths, nil opts handling for ebpf.LoadPinnedMap, cleanup via DestroyHook for enforcer handles, and a memory leak fix in libbpf bpf_program__attach_uprobe_multi. Overall impact: increased stability and reliability of instrumentation, reduced maintenance burden, improved resource management, and stronger observability. Technologies/skills demonstrated: Go and ebpf/libbpf ecosystems, Makefile and build-system modernization, LLVM IR object support, enhanced test automation and reliability, and kernel-probe based instrumentation.
During November 2024, the team delivered a set of stability, performance, and observability improvements across two repositories (cilium/tetragon and netdata/libbpf). Key features include: unconditional pinning of links and unpinning in unloader objects in tetragon; refactoring of unloader naming and related code paths; expanded test coverage and stability efforts (persistent enforcement tests, extra sleep in TestEnforcerMulti, and tests for exec events); symbol instances support in non-kprobe-multi specs with kprobe tests; build and tooling enhancements such as updating the ebpf dependency, enabling LLVM IR object builds, and comprehensive Makefile cleanup for cross-version support; and improved documentation for the BPF Makefile. Major user-facing and developer-impacting bugs fixed include: bugtool tracefs log dump, removal of program.LinkPin field, fixes for kprobe multi-attach and fmodret attach override link paths, nil opts handling for ebpf.LoadPinnedMap, cleanup via DestroyHook for enforcer handles, and a memory leak fix in libbpf bpf_program__attach_uprobe_multi. Overall impact: increased stability and reliability of instrumentation, reduced maintenance burden, improved resource management, and stronger observability. Technologies/skills demonstrated: Go and ebpf/libbpf ecosystems, Makefile and build-system modernization, LLVM IR object support, enhanced test automation and reliability, and kernel-probe based instrumentation.
October 2024 monthly summary for cilium/tetragon focusing on reliability, observability, and developer productivity. Completed a major Sensor Manager overhaul, standardized policy metrics labels, stabilized tests, and documented performance statistics to empower operators and engineers.
October 2024 monthly summary for cilium/tetragon focusing on reliability, observability, and developer productivity. Completed a major Sensor Manager overhaul, standardized policy metrics labels, stabilized tests, and documented performance statistics to empower operators and engineers.
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