I tried using a smaller period_size (about 1/16 of hwbuf_size),

snd_pcm_avail returned a better value.

Period bytes = 2Kbytes which is still larger than the default rewind_safeguard 512 bytes

But cpu usage moved from 1% to 4%, since we are using it in a

automotive, we don`t care about power saving, I think it is acceptable.

But I`m not sure if there is any other down side about "time based

scheduling" ?