On Sun, 12 Jan 2025 14:26:35 +0900 "Masami Hiramatsu (Google)" <[email protected]> wrote:
> From: Masami Hiramatsu (Google) <[email protected]> > > Since the ftrace_graph_ret::rettime is only referred in the function_graph > tracer, the trace_clock_local() call in fgraph is just an overhead for > other fgraph users. > > Move the trace_clock_local() for recording return time to function_graph > tracer and the rettime field is just zeroed in the fgraph side. > That rettime field is updated by one of the function_graph tracer and > cached for other function_graph tracer instances. > > According to Jiri's report[1], removing this function will gain fprobe > performance ~27%. > > [1] https://lore.kernel.org/all/Z3aSuql3fnXMVMoM@krava/ > > Reported-by: Jiri Olsa <[email protected]> > Signed-off-by: Masami Hiramatsu (Google) <[email protected]> I'd rather just nuke the calltime and rettime from struct ftrace_graph_ret. How about something like this instead? [ based on: https://lore.kernel.org/linux-trace-kernel/[email protected]/ ] I can start testing it (it compiles and boots). include/linux/ftrace.h | 2 -- kernel/trace/fgraph.c | 1 - kernel/trace/trace.h | 4 +++- kernel/trace/trace_entries.h | 8 +++---- kernel/trace/trace_functions_graph.c | 33 ++++++++++++++++------------ kernel/trace/trace_irqsoff.c | 5 +++-- kernel/trace/trace_sched_wakeup.c | 6 +++-- 7 files changed, 33 insertions(+), 26 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index aa9ddd1e4bb6..848ddf0d8f89 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -1061,8 +1061,6 @@ struct ftrace_graph_ret { int depth; /* Number of functions that overran the depth limit for current task */ unsigned int overrun; - unsigned long long calltime; - unsigned long long rettime; } __packed; struct fgraph_ops; diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 30e3ddc8a8a8..a7e6c8488b7f 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -818,7 +818,6 @@ static unsigned long __ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs return (unsigned long)panic; } - trace.rettime = trace_clock_local(); #ifdef CONFIG_FUNCTION_GRAPH_RETVAL trace.retval = fgraph_ret_regs_return_value(ret_regs); #endif diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 9691b47b5f3d..467a8143fbb9 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -911,7 +911,9 @@ extern int __trace_graph_retaddr_entry(struct trace_array *tr, unsigned long retaddr); extern void __trace_graph_return(struct trace_array *tr, struct ftrace_graph_ret *trace, - unsigned int trace_ctx); + unsigned int trace_ctx, + u64 calltime, u64 rettime); + extern void init_array_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops); extern int allocate_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops); extern void free_fgraph_ops(struct trace_array *tr); diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h index 82fd174ebbe0..fbfb396905a6 100644 --- a/kernel/trace/trace_entries.h +++ b/kernel/trace/trace_entries.h @@ -124,8 +124,8 @@ FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry, __field_packed( unsigned long, ret, retval ) __field_packed( int, ret, depth ) __field_packed( unsigned int, ret, overrun ) - __field_packed( unsigned long long, ret, calltime) - __field_packed( unsigned long long, ret, rettime ) + __field(unsigned long long, calltime ) + __field(unsigned long long, rettime ) ), F_printk("<-- %ps (%d) (start: %llx end: %llx) over: %d retval: %lx", @@ -146,8 +146,8 @@ FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry, __field_packed( unsigned long, ret, func ) __field_packed( int, ret, depth ) __field_packed( unsigned int, ret, overrun ) - __field_packed( unsigned long long, ret, calltime) - __field_packed( unsigned long long, ret, rettime ) + __field(unsigned long long, calltime ) + __field(unsigned long long, rettime ) ), F_printk("<-- %ps (%d) (start: %llx end: %llx) over: %d", diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 5504b5e4e7b4..7bff133c1543 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -270,12 +270,10 @@ __trace_graph_function(struct trace_array *tr, struct ftrace_graph_ret ret = { .func = ip, .depth = 0, - .calltime = time, - .rettime = time, }; __trace_graph_entry(tr, &ent, trace_ctx); - __trace_graph_return(tr, &ret, trace_ctx); + __trace_graph_return(tr, &ret, trace_ctx, time, time); } void @@ -287,8 +285,9 @@ trace_graph_function(struct trace_array *tr, } void __trace_graph_return(struct trace_array *tr, - struct ftrace_graph_ret *trace, - unsigned int trace_ctx) + struct ftrace_graph_ret *trace, + unsigned int trace_ctx, + u64 calltime, u64 rettime) { struct ring_buffer_event *event; struct trace_buffer *buffer = tr->array_buffer.buffer; @@ -300,6 +299,8 @@ void __trace_graph_return(struct trace_array *tr, return; entry = ring_buffer_event_data(event); entry->ret = *trace; + entry->calltime = calltime; + entry->rettime = rettime; trace_buffer_unlock_commit_nostack(buffer, event); } @@ -322,10 +323,13 @@ void trace_graph_return(struct ftrace_graph_ret *trace, struct fgraph_times *ftimes; unsigned long flags; unsigned int trace_ctx; + u64 calltime, rettime; long disabled; int size; int cpu; + rettime = trace_clock_local(); + ftrace_graph_addr_finish(gops, trace); if (*task_var & TRACE_GRAPH_NOTRACE) { @@ -339,7 +343,7 @@ void trace_graph_return(struct ftrace_graph_ret *trace, handle_nosleeptime(trace, ftimes, size); - trace->calltime = ftimes->calltime; + calltime = ftimes->calltime; local_irq_save(flags); cpu = raw_smp_processor_id(); @@ -347,7 +351,7 @@ void trace_graph_return(struct ftrace_graph_ret *trace, disabled = atomic_inc_return(&data->disabled); if (likely(disabled == 1)) { trace_ctx = tracing_gen_ctx_flags(flags); - __trace_graph_return(tr, trace, trace_ctx); + __trace_graph_return(tr, trace, trace_ctx, calltime, rettime); } atomic_dec(&data->disabled); local_irq_restore(flags); @@ -372,10 +376,8 @@ static void trace_graph_thresh_return(struct ftrace_graph_ret *trace, handle_nosleeptime(trace, ftimes, size); - trace->calltime = ftimes->calltime; - if (tracing_thresh && - (trace->rettime - ftimes->calltime < tracing_thresh)) + (trace_clock_local() - ftimes->calltime < tracing_thresh)) return; else trace_graph_return(trace, gops); @@ -861,7 +863,7 @@ print_graph_entry_leaf(struct trace_iterator *iter, graph_ret = &ret_entry->ret; call = &entry->graph_ent; - duration = graph_ret->rettime - graph_ret->calltime; + duration = ret_entry->rettime - ret_entry->calltime; func = call->func + iter->tr->text_delta; @@ -1142,11 +1144,14 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s, } static enum print_line_t -print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, +print_graph_return(struct ftrace_graph_ret_entry *retentry, struct trace_seq *s, struct trace_entry *ent, struct trace_iterator *iter, u32 flags) { - unsigned long long duration = trace->rettime - trace->calltime; + struct ftrace_graph_ret *trace = &retentry->ret; + u64 calltime = retentry->calltime; + u64 rettime = retentry->rettime; + unsigned long long duration = rettime - calltime; struct fgraph_data *data = iter->private; struct trace_array *tr = iter->tr; unsigned long func; @@ -1347,7 +1352,7 @@ print_graph_function_flags(struct trace_iterator *iter, u32 flags) case TRACE_GRAPH_RET: { struct ftrace_graph_ret_entry *field; trace_assign_type(field, entry); - return print_graph_return(&field->ret, s, entry, iter, flags); + return print_graph_return(field, s, entry, iter, flags); } case TRACE_STACK: case TRACE_FN: diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index a4e799c1e767..1d3646ce9c34 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -221,6 +221,7 @@ static void irqsoff_graph_return(struct ftrace_graph_ret *trace, unsigned long flags; unsigned int trace_ctx; u64 *calltime; + u64 rettime; int size; ftrace_graph_addr_finish(gops, trace); @@ -228,13 +229,13 @@ static void irqsoff_graph_return(struct ftrace_graph_ret *trace, if (!func_prolog_dec(tr, &data, &flags)) return; + rettime = trace_clock_local(); calltime = fgraph_retrieve_data(gops->idx, &size); if (!calltime) return; - trace->calltime = *calltime; trace_ctx = tracing_gen_ctx_flags(flags); - __trace_graph_return(tr, trace, trace_ctx); + __trace_graph_return(tr, trace, trace_ctx, *calltime, rettime); atomic_dec(&data->disabled); } diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index c58292e424d5..c4bbaae2a2a3 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -156,6 +156,7 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace, struct trace_array_cpu *data; unsigned int trace_ctx; u64 *calltime; + u64 rettime; int size; ftrace_graph_addr_finish(gops, trace); @@ -163,12 +164,13 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace, if (!func_prolog_preempt_disable(tr, &data, &trace_ctx)) return; + rettime = trace_clock_local(); + calltime = fgraph_retrieve_data(gops->idx, &size); if (!calltime) return; - trace->calltime = *calltime; - __trace_graph_return(tr, trace, trace_ctx); + __trace_graph_return(tr, trace, trace_ctx, *calltime, rettime); atomic_dec(&data->disabled); preempt_enable_notrace(); -- 2.45.2 -- Steve
