perf report shows this function “__memset_avx2_unaligned_erms” has overhead. does this mean memory is unaligned?
Clash Royale CLAN TAG #URR8PPP perf report shows this function “__memset_avx2_unaligned_erms” has overhead. does this mean memory is unaligned? I am trying to profile my C++ code using perf tool. Implementation contains code with SSE/AVX/AVX2 instructions. In addition to that code is compiled with -O3 -mavx2 -march=native flags. I believe __memset_avx2_unaligned_erms function is a libc implementation of memset . perf shows that this function has considerable overhead. Function name indicates that memory is unaligned, however in the code I am explicitly aligning the memory using GCC built-in macro __attribute__((aligned (x))) What might be the reason for this function to have significant overhead and also why unaligned version is called although memory is aligned explicitly? -O3 -mavx2 -march=native __memset_avx2_unaligned_erms memset __attribute__((aligned (x))) I have attached the sample report as picture. memset happens to be implemented in a way that d...