so I was looking at the following code, from dynamic_debug.c, I saw a minor code optimization, and wondered whether its already optimized away by compiler. Instead of actually testing it ( I intend to eventually ) I figure Id ask if you all want to take an educated guess ? or perhaps just do the test, and post results. And since Im making a game of it, I might suggest a prize - that by prepping a patch, showing its effect (none? tiny? not observable in objdump?) and submitting it, I would ack it I suspect that Greg might take it ; its a legit sub-optimality and fix is at least decluttering and deobfuscating. so heres the snippet. if you got this far, you can find the prob (or 2) static char *dynamic_emit_prefix(struct _ddebug *dp, char *buf) { int pos_after_tid; int pos = 0; *buf = '\0'; if (dp->flags & _DPRINTK_FLAGS_INCL_TID) { if (in_interrupt()) pos += snprintf(buf + pos, remaining(pos), "<intr> "); else pos += snprintf(buf + pos, remaining(pos), "[%d] ", task_pid_vnr(current)); }