I'm having trouble finding reliable information about the performance of unaligned NEON memory access on ARMv7 phones.
What I can find is: * ARMv7 seems to allow unaligned access to be a trap-to-kernel kind of performance disaster, but it's hard to find information about whether the phone SoCs we care about are actually disastrous like that. * On aarch64, unaligned access is the same instruction as aligned access and gets dynamically penalized, but only minimally, if the access crosses a cache line boundary. *Presumably* ARMv7 code running on an ARMv8 core gets the same benefit. Do we know what performance characteristics we can assume for unaligned NEON loads/stores on Android phones that have ARMv7 cores and recent enough Android that Fennec runs in the first place? -- Henri Sivonen hsivo...@hsivonen.fi https://hsivonen.fi/ _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
