Andi Kleen wrote: > One thing I was pondering was to replace the expensive popfs with > > bt $IF,(%rsp) > jnc 1f > sti > 1: > > But would be mostly a P4 optimization again and I'm not 100% sure it is > worth it. >
Worth it on 32-bit. On AMD64, probably not. On Intel 64-bit, maybe, but less important than in P4 days. This could change character completely if used at the tail of a function where you now have sti; 1: ret Which generates an interrupt holdoff on the ret, an unusual thing to do. Zach _______________________________________________ Virtualization mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/virtualization
