Hi Aneesh, > yes. We do use jump label. I also verified that looking at .s > > #APP > # 23 "./arch/powerpc/include/asm/jump_label.h" 1 > 1: > nop > .pushsection __jump_table, "aw" > .llong 1b, .L201, __tracepoint_hash_fault+8 #, > .popsection > > # 0 "" 2
So we insert a single nop, and the slow path is in another section. I'd be surprised if we could measure this, unless the nop causes a branch target alignment issue the slow path caused some hot path icache layout issues. > Without patch > sys: 0m11.2425 > > With patch: > sys: 0m11.3258 > > ie, a -0.7% impact > > If that impact is high we could possibly put that tracepoint within > #ifdef CONFIG_DEBUG_VM ? Did the real time change? I'd be careful about comparing based on system time. My feeling is we should not hide it behind CONFIG_DEBUG_VM. Anton _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
