Messages in this thread | | | Date | Sat, 11 Sep 2021 09:59:37 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH 1/2] scripts: ftrace - move the sort-processing in ftrace_init to compile time |
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On Sat, 11 Sep 2021 21:50:42 +0800 Yinan Liu <yinan@linux.alibaba.com> wrote:
> When ftrace is enabled, ftrace_init will consume a period of > time, usually around 15~20 ms. Approximately 40% of the time is > consumed by sort-processing. Moving the sort-processing to the > compile time can speed up the kernel boot process. >
Nice. I like the idea of sorting at compile time.
> performance test: > env: Intel(R) Xeon(R) CPU E5-2682 v4 @ 2.50GHz > method: before and after patching, compare the > total time of ftrace_init(), and verify > the functionality of ftrace. > > avg_time of ftrace_init: > with patch: 8.352 ms > without patch: 15.763 ms > > Signed-off-by: Yinan Liu <yinan@linux.alibaba.com> > --- > kernel/trace/ftrace.c | 5 ++- > scripts/link-vmlinux.sh | 6 +-- > scripts/sorttable.c | 2 + > scripts/sorttable.h | 109 +++++++++++++++++++++++++++++++++++++++++++++++- > 4 files changed, 115 insertions(+), 7 deletions(-) > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > index 7efbc8aaf7f6..c236da868990 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -6189,8 +6189,9 @@ static int ftrace_process_locs(struct module *mod, > if (!count) > return 0; > > - sort(start, count, sizeof(*start), > - ftrace_cmp_ips, NULL); > + if (mod)
Why can't we enforce modules to be sorted too?
> + sort(start, count, sizeof(*start), > + ftrace_cmp_ips, NULL);
-- Steve
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