On 07 Dec 2015, at 09:12, Harald Welte laforge@gnumonks.org wrote:
Hi all,
- vfprintf() and friends, from logp() statements. The sad part is that
calls like gsm_lchan_name() are of course executed beefore the call into logp(), at which point the vfprintf/sprintf/... for arguments has already been executed, and only the last/final one hasn't happened yet.
Jacob has proposed (and I think maybe included) a patch to check if logging is enabled for any target before making the call (and passing the arguments)
After a brief look at osmo-pcu profiling, it looks like in the attached picture. We cannot do much about the __copy_to_user_std, do_select and core_sys_select, as those are kernel side.
epoll. We avoid transferring FD set to the kernel all the time (and arming them in the driver). But I assume the bigger cost of to user is the indications we copy from the DSP to userspace.