Re: [PATCH v2 00/10] tracing/boot: Add histogram syntax support in boot-time tracing

[Masami Hiramatsu <mhiramat@kernel.org>]

Oops, I forgot to update the title. This is v3.

On Tue, 10 Aug 2021 00:47:49 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Hi,
> 
> Here is the 3rd version of boot-time tracing to add histogram
> syntax extension with a bugfix related hist-trigger.
> 
> In this version, I updated the first bugfix to use IS_ENABLED()
> and show error if CONFIG_HIST_TRIGGERS=n ([1/10]), allow the spaces
> in the variable expressions ([2/10]), and update ktest bootconfig
> testcase ([10/10]).
> 
> 
> 'Histogram' options
> -------------------
> Currently, the boot-time tracing only supports per-event actions
> for setting trigger actions. This is enough for short actions
> like 'traceon', 'traceoff', 'snapshot' etc. However, it is not good
> for the 'hist' trigger action because it is usually too long to write
> it in a single string especially if it has an 'onmatch' action.
> 
> Here is the new syntax.
> 
>     ftrace[.instance.INSTANCE].event.GROUP.EVENT.hist[.N] {
>          keys = <KEY>[,...]
>          values = <VAL>[,...]
>          sort = <SORT-KEY>[,...]
>          size = <ENTRIES>
>          name = <HISTNAME>
>          var { <VAR> = <EXPR> ... }
>          pause|continue|clear
>          onmax|onchange[.M] { var = <VAR>, <ACTION> [= <PARAM>] }
>          onmatch[.M] { event = <EVENT>, <ACTION> [= <PARAM>] }
>          filter = <FILTER>
>     }
>     
> Where <ACTION> is one of below;
>     
>     trace = <EVENT>, <ARG1>[, ...]
>     save = <ARG1>[, ...]
>     snapshot
> 
> And "N" and "M" are digit started strings for multiple histograms
> and actions.
> 
> For example,
> 
> initcall.initcall_finish.actions =
> "hist:keys=func:lat=common_timestamp.usecs-$ts0:onmatch(initcall.initcall_start).trace(initcall_latency,func,$lat)"
> 
> This can be written as below;
> 
> initcall.initcall_finish.hist {
>     keys = func
>     var.lat = common_timestamp.usecs-$ts0
>     onmatch {
>         event = initcall.initcall_start
>         trace = initcall_latency, func, $lat
>     }
> }
> 
> Also, you can add comments for each options.
> 
> 
> Thank you,
> 
> ---
> 
> Masami Hiramatsu (10):
>       tracing/boot: Fix a hist trigger dependency for boot time tracing
>       tracing/boot: Add per-event histogram action options
>       tracing/boot: Support multiple handlers for per-event histogram
>       tracing/boot: Support multiple histograms for each event
>       tracing/boot: Show correct histogram error command
>       Documentation: tracing: Add histogram syntax to boot-time tracing
>       tools/bootconfig: Support per-group/all event enabling option
>       tools/bootconfig: Add histogram syntax support to bconf2ftrace.sh
>       tools/bootconfig: Use per-group/all enable option in ftrace2bconf script
>       bootconfig/tracing/ktest: Update ktest example for boot-time tracing
> 
> 
>  Documentation/trace/boottime-trace.rst             |   85 +++++-
>  kernel/trace/trace_boot.c                          |  301 ++++++++++++++++++++
>  tools/bootconfig/scripts/bconf2ftrace.sh           |   97 ++++++
>  tools/bootconfig/scripts/ftrace2bconf.sh           |   24 +-
>  tools/bootconfig/scripts/xbc.sh                    |    4 
>  .../ktest/examples/bootconfigs/boottrace.bconf     |   20 +
>  .../ktest/examples/bootconfigs/verify-boottrace.sh |    2 
>  7 files changed, 508 insertions(+), 25 deletions(-)
> 
> -- 
> Masami Hiramatsu (Linaro) <mhiramat@kernel.org>


-- 
Masami Hiramatsu <mhiramat@kernel.org>