
Lazar Djurovic developed and optimized low-level kernel and testing infrastructure across the tenstorrent/tt-llk and tenstorrent/tt-metal repositories, focusing on matrix operations, attention kernels, and hardware validation. He engineered robust test frameworks and expanded support for multi-format data, including FP16, FP32, and low-precision formats, using C++ and Python. His work included performance tuning for Scaled Dot-Product Attention, atomic synchronization for SFPU operations, and enhancements to packing and reduction workflows. By integrating AI-generated tests and improving code governance, Lazar delivered reliable, maintainable systems that accelerated validation cycles and improved numerical fidelity, demonstrating depth in embedded systems, algorithm optimization, and concurrent programming.
April 2026 monthly summary for tenstorrent/tt-metal: Delivered a row-wise maximum reduction feature for floating-point operations with multiformat support, achieving FP32 precision on the SFPU path. Added support for Int32 and float16_b formats, and expanded test coverage for edge cases. Implemented LLK kernel with Python tests, broadened stimulus ranges, and addressed sign/magnitude handling in LLKs. Strengthened the test harness ensuring existing C++ tests remain green. This work improves numerical fidelity, broadens data-format support, and enhances reliability for training workloads.
April 2026 monthly summary for tenstorrent/tt-metal: Delivered a row-wise maximum reduction feature for floating-point operations with multiformat support, achieving FP32 precision on the SFPU path. Added support for Int32 and float16_b formats, and expanded test coverage for edge cases. Implemented LLK kernel with Python tests, broadened stimulus ranges, and addressed sign/magnitude handling in LLKs. Strengthened the test harness ensuring existing C++ tests remain green. This work improves numerical fidelity, broadens data-format support, and enhances reliability for training workloads.
March 2026 — tt-metal focused on strengthening governance and expanding test coverage for low-precision numeric formats. Key features delivered include establishing explicit code ownership for Blackhole and Wormhole components to improve governance, accountability, and maintenance workflows; and extending the testing infrastructure to support low-precision formats (bfp4_b and bfp8_b) with packing/unpacking, golden generation, and quantization. A major enhancement to matmul tests adds bfp8_b support by converting to float16_b for processing and broadening golden generation to handle multiple formats. Major bugs fixed include closing governance gaps and stabilizing CI for the new formats by addressing test-infra edge cases and ensuring consistent golden data across formats. Overall impact: stronger code ownership, more reliable testing across low-precision formats, reduced risk in releases, and faster onboarding for contributions. Technologies/skills demonstrated: code ownership management, testing infrastructure design and quantization, data-format handling, CI automation, and cross-format golden data workflows.
March 2026 — tt-metal focused on strengthening governance and expanding test coverage for low-precision numeric formats. Key features delivered include establishing explicit code ownership for Blackhole and Wormhole components to improve governance, accountability, and maintenance workflows; and extending the testing infrastructure to support low-precision formats (bfp4_b and bfp8_b) with packing/unpacking, golden generation, and quantization. A major enhancement to matmul tests adds bfp8_b support by converting to float16_b for processing and broadening golden generation to handle multiple formats. Major bugs fixed include closing governance gaps and stabilizing CI for the new formats by addressing test-infra edge cases and ensuring consistent golden data across formats. Overall impact: stronger code ownership, more reliable testing across low-precision formats, reduced risk in releases, and faster onboarding for contributions. Technologies/skills demonstrated: code ownership management, testing infrastructure design and quantization, data-format handling, CI automation, and cross-format golden data workflows.
February 2026 monthly summary focusing on performance-oriented matrix operations and SDPA-based accelerations in tt-llk, with improvements to packing throughput and code hygiene across the llk path.
February 2026 monthly summary focusing on performance-oriented matrix operations and SDPA-based accelerations in tt-llk, with improvements to packing throughput and code hygiene across the llk path.
Month 2025-12 focused on performance, correctness, and data-path robustness in the SFPU and data movement stack for tt-llk. Delivered two major features that improve throughput and data processing capabilities, and fixed a critical synchronization bug to ensure data integrity across SFPU operations. The work enhances matmul performance on WH cards and provides a more reliable execution path for SFPU-related kernels.
Month 2025-12 focused on performance, correctness, and data-path robustness in the SFPU and data movement stack for tt-llk. Delivered two major features that improve throughput and data processing capabilities, and fixed a critical synchronization bug to ensure data integrity across SFPU operations. The work enhances matmul performance on WH cards and provides a more reliable execution path for SFPU-related kernels.
November 2025 monthly summary for tenstorrent/tt-llk: Delivered the SDPA SFPU Maximum Column Reduction feature and enhanced performance/validation capabilities for the SDPA path. Implemented a targeted 4x2 subblock reduction in the SFPU output from transposed matmul, with accompanying tests and perf measurement to quantify gains. The work supports higher-throughput SDPA workloads and expands functional coverage in the SFPU optimization path.
November 2025 monthly summary for tenstorrent/tt-llk: Delivered the SDPA SFPU Maximum Column Reduction feature and enhanced performance/validation capabilities for the SDPA path. Implemented a targeted 4x2 subblock reduction in the SFPU output from transposed matmul, with accompanying tests and perf measurement to quantify gains. The work supports higher-throughput SDPA workloads and expands functional coverage in the SFPU optimization path.
October 2025: Focused on performance optimization in the SDPA path for tenstorrent/tt-llk. Implemented unpacker and kernel enhancements to enable element-wise subtraction between column tiles and tiled data, accelerating Scaled Dot-Product Attention. Added comprehensive tests and configuration options to validate the optimized path. The change is captured in commit 4de2e5b0b5b03da1297b5473b8ecb0ac94f92138.
October 2025: Focused on performance optimization in the SDPA path for tenstorrent/tt-llk. Implemented unpacker and kernel enhancements to enable element-wise subtraction between column tiles and tiled data, accelerating Scaled Dot-Product Attention. Added comprehensive tests and configuration options to validate the optimized path. The change is captured in commit 4de2e5b0b5b03da1297b5473b8ecb0ac94f92138.
September 2025: Focused on strengthening test infrastructure and performance visibility for the SDPA path in tt-metal. Delivered enhanced testing framework, introduced performance profiling capabilities, and validated multi-core test execution, enabling data-driven optimizations and faster QA cycles.
September 2025: Focused on strengthening test infrastructure and performance visibility for the SDPA path in tt-metal. Delivered enhanced testing framework, introduced performance profiling capabilities, and validated multi-core test execution, enabling data-driven optimizations and faster QA cycles.
August 2025 performance highlights across tt-llk and tt-metal, focusing on expanded test coverage, kernel optimization, and reliability improvements that drive faster validation and better performance characteristics for fused operations and attention kernels.
August 2025 performance highlights across tt-llk and tt-metal, focusing on expanded test coverage, kernel optimization, and reliability improvements that drive faster validation and better performance characteristics for fused operations and attention kernels.
July 2025 performance and reliability month focused on expanding kernel capabilities, improving test fidelity, and delivering measurable performance gains across tt-llk and tt-metal. Key accomplishments include expanding multi-tile support for core operations in tt-llk (unpack untilize, SFPU tests, and matmul) to handle multi-tile inputs for square tensors; introducing ttnn.where for LLK with SFPU kernels and associated API cleanup and iteration handling; implementing fidelity masking in test infrastructure to enhance accuracy of golden data for element-wise operations and matmul; and a performance optimization in tt-metal via a shift-and-add multiplication algorithm for int32 to reduce operation count and improve throughput.
July 2025 performance and reliability month focused on expanding kernel capabilities, improving test fidelity, and delivering measurable performance gains across tt-llk and tt-metal. Key accomplishments include expanding multi-tile support for core operations in tt-llk (unpack untilize, SFPU tests, and matmul) to handle multi-tile inputs for square tensors; introducing ttnn.where for LLK with SFPU kernels and associated API cleanup and iteration handling; implementing fidelity masking in test infrastructure to enhance accuracy of golden data for element-wise operations and matmul; and a performance optimization in tt-metal via a shift-and-add multiplication algorithm for int32 to reduce operation count and improve throughput.
June 2025: Major upgrade to the SFPU testing framework in tenstorrent/tt-llk, delivering tile-level and multi-tile test capabilities and binary test execution, along with improved utilities (parameterization, address generation, tile-count handling). Fixed targeted reliability issues in fidelity-based test selection and SFPI v_if path to reduce flaky failures and ensure correct operation paths. This work expands hardware validation coverage, accelerates feedback, and demonstrates proficiency in test automation, hardware-software integration, and CI readiness.
June 2025: Major upgrade to the SFPU testing framework in tenstorrent/tt-llk, delivering tile-level and multi-tile test capabilities and binary test execution, along with improved utilities (parameterization, address generation, tile-count handling). Fixed targeted reliability issues in fidelity-based test selection and SFPI v_if path to reduce flaky failures and ensure correct operation paths. This work expands hardware validation coverage, accelerates feedback, and demonstrates proficiency in test automation, hardware-software integration, and CI readiness.
May 2025 monthly summary for tenstorrent/tt-llk: Focused on strengthening test reliability and coverage through targeted test-suite improvements and a stability fix for cosine tests. Key progress: reduced flaky failures, improved parametrization, and clearer test instrumentation; enabling faster feedback and safer releases.
May 2025 monthly summary for tenstorrent/tt-llk: Focused on strengthening test reliability and coverage through targeted test-suite improvements and a stability fix for cosine tests. Key progress: reduced flaky failures, improved parametrization, and clearer test instrumentation; enabling faster feedback and safer releases.
April 2025 monthly summary for tenstorrent/tt-llk. Delivered a focused matmul test correctness fix and test harness cleanup, improving reliability and establishing a solid base for matrix operation validation. The changes corrected the element read order in unpack.py, updated the C++ test template arguments, and implemented a standard 3-loop matrix multiplication with input matrices stored in L1. Enabled testing with two random tiles in Float16_b format, and performed Packer code cleanup as part of the fix. These improvements reduce flaky tests, lower CI risk, and accelerate future matmul validation and integration work.
April 2025 monthly summary for tenstorrent/tt-llk. Delivered a focused matmul test correctness fix and test harness cleanup, improving reliability and establishing a solid base for matrix operation validation. The changes corrected the element read order in unpack.py, updated the C++ test template arguments, and implemented a standard 3-loop matrix multiplication with input matrices stored in L1. Enabled testing with two random tiles in Float16_b format, and performed Packer code cleanup as part of the fix. These improvements reduce flaky tests, lower CI risk, and accelerate future matmul validation and integration work.
March 2025 monthly summary for tenstorrent/tt-llk: Stabilized utilization instrumentation across architectures by fixing unpack_tilize for the Blackhole (BH) architecture, addressing a regression that caused test failures. The patch ensures unpack_tilize tests pass on both Whitehole (WH) and BH, and enables test_tilize_calculate_untilize to pass, reducing flaky tests and improving reliability of utilization metrics used for performance evaluation and capacity planning. Impact: Higher confidence in cross-arch performance data, reduced flaky test behavior, and improved foundation for optimization cycles across BH and WH deployments.
March 2025 monthly summary for tenstorrent/tt-llk: Stabilized utilization instrumentation across architectures by fixing unpack_tilize for the Blackhole (BH) architecture, addressing a regression that caused test failures. The patch ensures unpack_tilize tests pass on both Whitehole (WH) and BH, and enables test_tilize_calculate_untilize to pass, reducing flaky tests and improving reliability of utilization metrics used for performance evaluation and capacity planning. Impact: Higher confidence in cross-arch performance data, reduced flaky test behavior, and improved foundation for optimization cycles across BH and WH deployments.
February 2025: Focused on establishing a robust testing foundation for LLK and TenSIX firmware groundwork. No major defects fixed this month; work concentrated on infrastructure, cross-format and cross-architecture test readiness, and laying groundwork for TenSIX RISC-V firmware validation.
February 2025: Focused on establishing a robust testing foundation for LLK and TenSIX firmware groundwork. No major defects fixed this month; work concentrated on infrastructure, cross-format and cross-architecture test readiness, and laying groundwork for TenSIX RISC-V firmware validation.

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