On Wed, 27 Oct 2021 13:59:08 -0700 Kalesh Singh kaleshsingh@google.com wrote:
Update the tracefs README to describe how hist trigger variables can be created.
Signed-off-by: Kalesh Singh kaleshsingh@google.com
This looks good to me.
Acked-by: Masami Hiramatsu mhiramat@kernel.org
Thank you!
kernel/trace/trace.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index bc677cd64224..c41b3786401d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5628,6 +5628,7 @@ static const char readme_msg[] = #ifdef CONFIG_HIST_TRIGGERS " hist trigger\t- If set, event hits are aggregated into a hash table\n" "\t Format: hist:keys=<field1[,field2,...]>\n"
- "\t [:<var1>=<field|var_ref|numeric_literal>[,<var2>=...]]\n" "\t [:values=<field1[,field2,...]>]\n" "\t [:sort=<field1[,field2,...]>]\n" "\t [:size=#entries]\n"
@@ -5639,6 +5640,16 @@ static const char readme_msg[] = "\t common_timestamp - to record current timestamp\n" "\t common_cpu - to record the CPU the event happened on\n" "\n"
- "\t A hist trigger variable can be:\n"
- "\t - a reference to a field e.g. x=current_timestamp,\n"
- "\t - a reference to another variable e.g. y=$x,\n"
- "\t - a numeric literal: e.g. ms_per_sec=1000,\n"
- "\t - an arithmetic expression: e.g. time_secs=current_timestamp/1000\n"
- "\n"
- "\t hist trigger aritmethic expressions support addition(+), subtraction(-),\n"
- "\t multiplication(*) and division(/) operators. An operand can be either a\n"
- "\t variable reference, field or numeric literal.\n"
- "\n" "\t When a matching event is hit, an entry is added to a hash\n" "\t table using the key(s) and value(s) named, and the value of a\n" "\t sum called 'hitcount' is incremented. Keys and values\n"
-- 2.33.0.1079.g6e70778dc9-goog