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METIS is the Mid-infrared E-ELT Imager and Spectrograph, one of three first generation instruments of the European Extremly Large Telescope (E-ELT). The primary mirror of the E-ELT has a diameter of 39 meter. This huge aperture requires an adaptive optics system in order to provide the performance close to the diffraction limit that is needed for all scientific observing modes of METIS. METIS will be be equipped with a single conjugated adaptive optics (SCAO) system that makes use of a near-infrared wavefront sensor. A real-time computer (RTC) reconstructs the wavefront and sends correction commands to the deformable mirror M4 and the field stabilization mirror M5. The METIS SCAO team evaluates computer workstations with the many-core processor Intel® Xeon Phi™ Knights Landing (KNL) for the real-time computation within the wavefront control loop. This processor is a promising candidate to satisfy the METIS AO needs as it allows for massively parallel computations. This parallelization is achieved by utilizing up to 272 logical CPUs, the new SIMD (single instruction, multiple data) instruction set AVX-512 and the high-bandwidth on-CPU memory MCDRAM. This paper describes the SCAO RTC concept, evaluates the computational performance that a wavefront control loop could have when using a Xeon Phi KNL, and compares it to the identified requirements. The measurements will be conducted with the AO system software of the LINC-NIRVANA project under Linux. Especially, the real-time capability is analyzed.
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