On 2025/9/23 19:10 Jiri Olsa <[email protected]> write: > On Tue, Sep 23, 2025 at 05:20:01PM +0800, Menglong Dong wrote: > > For now, fgraph is used for the fprobe, even if we need trace the entry > > only. However, the performance of ftrace is better than fgraph, and we > > can use ftrace_ops for this case. > > > > Then performance of kprobe-multi increases from 54M to 69M. Before this > > commit: > > > > $ ./benchs/run_bench_trigger.sh kprobe-multi > > kprobe-multi : 54.663 ± 0.493M/s > > > > After this commit: > > > > $ ./benchs/run_bench_trigger.sh kprobe-multi > > kprobe-multi : 69.447 ± 0.143M/s > > > > Mitigation is disable during the bench testing above. > > > > Signed-off-by: Menglong Dong <[email protected]> > > --- > > kernel/trace/fprobe.c | 88 +++++++++++++++++++++++++++++++++++++++---- > > 1 file changed, 81 insertions(+), 7 deletions(-) > > > > diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c > > index 1785fba367c9..de4ae075548d 100644 > > --- a/kernel/trace/fprobe.c > > +++ b/kernel/trace/fprobe.c > > @@ -292,7 +292,7 @@ static int fprobe_fgraph_entry(struct ftrace_graph_ent > > *trace, struct fgraph_ops > > if (node->addr != func) > > continue; > > fp = READ_ONCE(node->fp); > > - if (fp && !fprobe_disabled(fp)) > > + if (fp && !fprobe_disabled(fp) && > > fp->exit_handler) > > fp->nmissed++; > > } > > return 0; > > @@ -312,11 +312,11 @@ static int fprobe_fgraph_entry(struct > > ftrace_graph_ent *trace, struct fgraph_ops > > if (node->addr != func) > > continue; > > fp = READ_ONCE(node->fp); > > - if (!fp || fprobe_disabled(fp)) > > + if (unlikely(!fp || fprobe_disabled(fp) || !fp->exit_handler)) > > continue; > > > > data_size = fp->entry_data_size; > > - if (data_size && fp->exit_handler) > > + if (data_size) > > data = fgraph_data + used + FPROBE_HEADER_SIZE_IN_LONG; > > else > > data = NULL; > > @@ -327,7 +327,7 @@ static int fprobe_fgraph_entry(struct ftrace_graph_ent > > *trace, struct fgraph_ops > > ret = __fprobe_handler(func, ret_ip, fp, fregs, data); > > > > /* If entry_handler returns !0, nmissed is not counted but > > skips exit_handler. */ > > - if (!ret && fp->exit_handler) { > > + if (!ret) { > > int size_words = SIZE_IN_LONG(data_size); > > > > if (write_fprobe_header(&fgraph_data[used], fp, > > size_words)) > > @@ -384,6 +384,70 @@ static struct fgraph_ops fprobe_graph_ops = { > > }; > > static int fprobe_graph_active; > > > > +/* ftrace_ops backend (entry-only) */ > > +static void fprobe_ftrace_entry(unsigned long ip, unsigned long parent_ip, > > + struct ftrace_ops *ops, struct ftrace_regs *fregs) > > +{ > > + struct fprobe_hlist_node *node; > > + struct rhlist_head *head, *pos; > > + struct fprobe *fp; > > + > > + guard(rcu)(); > > + head = rhltable_lookup(&fprobe_ip_table, &ip, fprobe_rht_params); > > hi, > so this is based on yout previous patch, right? > fprobe: use rhltable for fprobe_ip_table > > would be better to mention that.. is there latest version of that somewhere?
Yeah, this is based on that version. That patch is applied to: https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git/log/?h=probes%2Ffor-next And I do the testing on that branches. Thanks! Menglong Dong > > thanks, > jirka > >
