Hi, >> All register reads/writes in rt2800usb were previously done with >> rt2800_register_read/rt2800_register_write. These however indirectly >> call rt2x00usb_register_read/rt2x00usb_register_write which adds an >> additional overhead of at least one call and several move instructions >> to each register access. >> >> Replacing the calls to rt2800_register_read/rt2800_register_write with >> direct calls to rt2x00usb_register_read/rt2x00usb_register_write gets >> rid of quite a number of instructions in the drivers hotpaths (IRQ >> handling and txdone handling). >> >> For consistency replace all references to rt2800_register_read/write >> with the rt2x00usb_register_read/write variants. > > This way you loose abstraction of writes/reads for usb vs. pci. And > you still can not optimize rt2800lib code which is shared between usb > and pci. Well the rt2800lib code is not changed by this (or patch 20 of this series). > Wouldn't this be better to create two pointers in struct rt2x00_dev. > One for writing function and one for reading function? Am I right > thinking calling functions by pointers is quite fast? Or is this still > noticeably slower than using proper functions directly? We already have the pointer inside struct rt2x00_dev which references the register access functions for rt2800pci/usb. These pointers are used by rt2800lib to access the common registers. What this patch does, is optimize the case where we exactly know which function we need, because we are in the actual driver. As for the performance, I'll let Helmut comment on that as he created patch 20, which introduced this change to rt2800pci. :) Ivo -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
