diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2025-03-06 13:01:27 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-03-06 13:03:35 -0800 |
| commit | 2525e16a2bae322641fd745412f3524d4455d8df (patch) | |
| tree | b1b2646362b8cc89fe3cf4eece698810fbb05c55 /kernel/trace/ftrace.c | |
| parent | f1078ab18818542a90e59be420448bd8034bc332 (diff) | |
| parent | f315296c92fd4b7716bdea17f727ab431891dc3b (diff) | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-6.14-rc6).
Conflicts:
net/ethtool/cabletest.c
2bcf4772e45a ("net: ethtool: try to protect all callback with netdev instance lock")
637399bf7e77 ("net: ethtool: netlink: Allow NULL nlattrs when getting a phy_device")
No Adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'kernel/trace/ftrace.c')
| -rw-r--r-- | kernel/trace/ftrace.c | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 6b0c25761ccb..fc88e0688daf 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -540,6 +540,7 @@ static int function_stat_show(struct seq_file *m, void *v) static struct trace_seq s; unsigned long long avg; unsigned long long stddev; + unsigned long long stddev_denom; #endif guard(mutex)(&ftrace_profile_lock); @@ -559,23 +560,19 @@ static int function_stat_show(struct seq_file *m, void *v) #ifdef CONFIG_FUNCTION_GRAPH_TRACER seq_puts(m, " "); - /* Sample standard deviation (s^2) */ - if (rec->counter <= 1) - stddev = 0; - else { - /* - * Apply Welford's method: - * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2) - */ + /* + * Variance formula: + * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2) + * Maybe Welford's method is better here? + * Divide only by 1000 for ns^2 -> us^2 conversion. + * trace_print_graph_duration will divide by 1000 again. + */ + stddev = 0; + stddev_denom = rec->counter * (rec->counter - 1) * 1000; + if (stddev_denom) { stddev = rec->counter * rec->time_squared - rec->time * rec->time; - - /* - * Divide only 1000 for ns^2 -> us^2 conversion. - * trace_print_graph_duration will divide 1000 again. - */ - stddev = div64_ul(stddev, - rec->counter * (rec->counter - 1) * 1000); + stddev = div64_ul(stddev, stddev_denom); } trace_seq_init(&s); |