On Wed, 2017-04-19 at 12:52:28 UTC, "Naveen N. Rao" wrote: > KPROBES_ON_FTRACE avoids much of the overhead with regular kprobes as it > eliminates the need for a trap, as well as the need to emulate or > single-step instructions. > > Though OPTPROBES provides us with similar performance, we have limited > optprobes trampoline slots. As such, when asked to probe at a function > entry, default to using the ftrace infrastructure. > > With: > # cd /sys/kernel/debug/tracing > # echo 'p _do_fork' > kprobe_events > > before patch: > # cat ../kprobes/list > c0000000000daf08 k _do_fork+0x8 [DISABLED] > c000000000044fc0 k kretprobe_trampoline+0x0 [OPTIMIZED] > > and after patch: > # cat ../kprobes/list > c0000000000d074c k _do_fork+0xc [DISABLED][FTRACE] > c0000000000412b0 k kretprobe_trampoline+0x0 [OPTIMIZED] > > Signed-off-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/24bd909e94776ecce95291bff910f1 cheers
