This letter presents a toolchain called HotSniper developed by integrating HotSpot temperature modeling tool with Sniper many-core simulator. HotSniper allows for interval thermal simulation of many-cores, which is several times faster than the cycle-accurate many-core thermal simulations and at the same time is more accurate than trace-based many-core thermal simulations. HotSniper toolchain provides efficient means to perform thermal-aware hardware-software codesign of many-core processors in domain of embedded systems. The source code for HotSniper has been made public.