Hi Liao, On Thu, 15 Aug 2024 01:46:29 +0000 Liao Chang <liaochang1@xxxxxxxxxx> wrote: > This patch introduces a flag to track TIF_SIGPENDING is suppress > temporarily during the uprobe single-step. Upon uprobe singlestep is > handled and the flag is confirmed, it could resume the TIF_SIGPENDING > directly without acquiring the siglock in most case, then reducing > contention and improving overall performance. > > I've use the script developed by Andrii in [1] to run benchmark. The CPU > used was Kunpeng916 (Hi1616), 4 NUMA nodes, 64 cores@2.4GHz running the > kernel on next tree + the optimization for get_xol_insn_slot() [2]. > > before-opt > ---------- > uprobe-nop ( 1 cpus): 0.907 ± 0.003M/s ( 0.907M/s/cpu) > uprobe-nop ( 2 cpus): 1.676 ± 0.008M/s ( 0.838M/s/cpu) > uprobe-nop ( 4 cpus): 3.210 ± 0.003M/s ( 0.802M/s/cpu) > uprobe-nop ( 8 cpus): 4.457 ± 0.003M/s ( 0.557M/s/cpu) > uprobe-nop (16 cpus): 3.724 ± 0.011M/s ( 0.233M/s/cpu) > uprobe-nop (32 cpus): 2.761 ± 0.003M/s ( 0.086M/s/cpu) > uprobe-nop (64 cpus): 1.293 ± 0.015M/s ( 0.020M/s/cpu) > > uprobe-push ( 1 cpus): 0.883 ± 0.001M/s ( 0.883M/s/cpu) > uprobe-push ( 2 cpus): 1.642 ± 0.005M/s ( 0.821M/s/cpu) > uprobe-push ( 4 cpus): 3.086 ± 0.002M/s ( 0.771M/s/cpu) > uprobe-push ( 8 cpus): 3.390 ± 0.003M/s ( 0.424M/s/cpu) > uprobe-push (16 cpus): 2.652 ± 0.005M/s ( 0.166M/s/cpu) > uprobe-push (32 cpus): 2.713 ± 0.005M/s ( 0.085M/s/cpu) > uprobe-push (64 cpus): 1.313 ± 0.009M/s ( 0.021M/s/cpu) > > uprobe-ret ( 1 cpus): 1.774 ± 0.000M/s ( 1.774M/s/cpu) > uprobe-ret ( 2 cpus): 3.350 ± 0.001M/s ( 1.675M/s/cpu) > uprobe-ret ( 4 cpus): 6.604 ± 0.000M/s ( 1.651M/s/cpu) > uprobe-ret ( 8 cpus): 6.706 ± 0.005M/s ( 0.838M/s/cpu) > uprobe-ret (16 cpus): 5.231 ± 0.001M/s ( 0.327M/s/cpu) > uprobe-ret (32 cpus): 5.743 ± 0.003M/s ( 0.179M/s/cpu) > uprobe-ret (64 cpus): 4.726 ± 0.016M/s ( 0.074M/s/cpu) > > after-opt > --------- > uprobe-nop ( 1 cpus): 0.985 ± 0.002M/s ( 0.985M/s/cpu) > uprobe-nop ( 2 cpus): 1.773 ± 0.005M/s ( 0.887M/s/cpu) > uprobe-nop ( 4 cpus): 3.304 ± 0.001M/s ( 0.826M/s/cpu) > uprobe-nop ( 8 cpus): 5.328 ± 0.002M/s ( 0.666M/s/cpu) > uprobe-nop (16 cpus): 6.475 ± 0.002M/s ( 0.405M/s/cpu) > uprobe-nop (32 cpus): 4.831 ± 0.082M/s ( 0.151M/s/cpu) > uprobe-nop (64 cpus): 2.564 ± 0.053M/s ( 0.040M/s/cpu) > > uprobe-push ( 1 cpus): 0.964 ± 0.001M/s ( 0.964M/s/cpu) > uprobe-push ( 2 cpus): 1.766 ± 0.002M/s ( 0.883M/s/cpu) > uprobe-push ( 4 cpus): 3.290 ± 0.009M/s ( 0.823M/s/cpu) > uprobe-push ( 8 cpus): 4.670 ± 0.002M/s ( 0.584M/s/cpu) > uprobe-push (16 cpus): 5.197 ± 0.004M/s ( 0.325M/s/cpu) > uprobe-push (32 cpus): 5.068 ± 0.161M/s ( 0.158M/s/cpu) > uprobe-push (64 cpus): 2.605 ± 0.026M/s ( 0.041M/s/cpu) > > uprobe-ret ( 1 cpus): 1.833 ± 0.001M/s ( 1.833M/s/cpu) > uprobe-ret ( 2 cpus): 3.384 ± 0.003M/s ( 1.692M/s/cpu) > uprobe-ret ( 4 cpus): 6.677 ± 0.004M/s ( 1.669M/s/cpu) > uprobe-ret ( 8 cpus): 6.854 ± 0.005M/s ( 0.857M/s/cpu) > uprobe-ret (16 cpus): 6.508 ± 0.006M/s ( 0.407M/s/cpu) > uprobe-ret (32 cpus): 5.793 ± 0.009M/s ( 0.181M/s/cpu) > uprobe-ret (64 cpus): 4.743 ± 0.016M/s ( 0.074M/s/cpu) > > Above benchmark results demonstrates a obivious improvement in the > scalability of trig-uprobe-nop and trig-uprobe-push, the peak throughput > of which are from 4.5M/s to 6.4M/s and 3.3M/s to 5.1M/s individually. > > [1] https://lore.kernel.org/all/20240731214256.3588718-1-andrii@xxxxxxxxxx > [2] https://lore.kernel.org/all/20240727094405.1362496-1-liaochang1@xxxxxxxxxx > This looks good to me. Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> Thanks, > Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx> > Signed-off-by: Liao Chang <liaochang1@xxxxxxxxxx> > --- > include/linux/uprobes.h | 1 + > kernel/events/uprobes.c | 8 +++++--- > 2 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h > index b503fafb7fb3..e4f57117d9c3 100644 > --- a/include/linux/uprobes.h > +++ b/include/linux/uprobes.h > @@ -75,6 +75,7 @@ struct uprobe_task { > > struct uprobe *active_uprobe; > unsigned long xol_vaddr; > + bool signal_denied; > > struct return_instance *return_instances; > unsigned int depth; > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > index 76a51a1f51e2..589aa2af1a99 100644 > --- a/kernel/events/uprobes.c > +++ b/kernel/events/uprobes.c > @@ -1979,6 +1979,7 @@ bool uprobe_deny_signal(void) > WARN_ON_ONCE(utask->state != UTASK_SSTEP); > > if (task_sigpending(t)) { > + utask->signal_denied = true; > clear_tsk_thread_flag(t, TIF_SIGPENDING); > > if (__fatal_signal_pending(t) || arch_uprobe_xol_was_trapped(t)) { > @@ -2288,9 +2289,10 @@ static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs) > utask->state = UTASK_RUNNING; > xol_free_insn_slot(current); > > - spin_lock_irq(¤t->sighand->siglock); > - recalc_sigpending(); /* see uprobe_deny_signal() */ > - spin_unlock_irq(¤t->sighand->siglock); > + if (utask->signal_denied) { > + set_thread_flag(TIF_SIGPENDING); > + utask->signal_denied = false; > + } > > if (unlikely(err)) { > uprobe_warn(current, "execute the probed insn, sending SIGILL."); > -- > 2.34.1 > > -- Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
