linux-kernel - Re: [PATCH 1/5] perf lock: Add flags field in the lock

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Date:   Mon, 25 Jul 2022 17:53:46 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Jiri Olsa <jolsa@...nel.org>, Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ian Rogers <irogers@...gle.com>,
        linux-perf-users@...r.kernel.org, Will Deacon <will@...nel.org>,
        Waiman Long <longman@...hat.com>,
        Boqun Feng <boqun.feng@...il.com>,
        Davidlohr Bueso <dave@...olabs.net>
Subject: Re: [PATCH 1/5] perf lock: Add flags field in the lock_stat

Em Mon, Jul 25, 2022 at 11:31:20AM -0700, Namhyung Kim escreveu:
> For lock contention tracepoint analysis, it needs to keep the flags.
> As nr_readlock and nr_trylock fields are not used for it, let's make
> it a union.
> 
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
>  tools/perf/builtin-lock.c | 22 +++++++++++++---------
>  1 file changed, 13 insertions(+), 9 deletions(-)
> 
> diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
> index 0aae88fdf93a..1de459198b99 100644
> --- a/tools/perf/builtin-lock.c
> +++ b/tools/perf/builtin-lock.c
> @@ -59,7 +59,10 @@ struct lock_stat {
>  	unsigned int		nr_contended;
>  	unsigned int		nr_release;
>  
> -	unsigned int		nr_readlock;
> +	union {
> +		unsigned int	nr_readlock;
> +		unsigned int	flags;
> +	};
>  	unsigned int		nr_trylock;
>  
>  	/* these times are in nano sec. */
> @@ -516,7 +519,7 @@ static struct lock_stat *lock_stat_find(u64 addr)
>  	return NULL;
>  }
>  
> -static struct lock_stat *lock_stat_findnew(u64 addr, const char *name)
> +static struct lock_stat *lock_stat_findnew(u64 addr, const char *name, int flags)
>  {
>  	struct hlist_head *entry = lockhashentry(addr);
>  	struct lock_stat *ret, *new;
> @@ -531,13 +534,13 @@ static struct lock_stat *lock_stat_findnew(u64 addr, const char *name)
>  		goto alloc_failed;
>  
>  	new->addr = addr;
> -	new->name = zalloc(sizeof(char) * strlen(name) + 1);
> +	new->name = strdup(name);
>  	if (!new->name) {
>  		free(new);
>  		goto alloc_failed;
>  	}
>  
> -	strcpy(new->name, name);

I'm applying to speed things up, but please separate such unrelated bits
in another patch next time.

- Arnaldo

> +	new->flags = flags;
>  	new->wait_time_min = ULLONG_MAX;
>  
>  	hlist_add_head(&new->hash_entry, entry);
> @@ -624,7 +627,7 @@ static int report_lock_acquire_event(struct evsel *evsel,
>  	if (show_thread_stats)
>  		addr = sample->tid;
>  
> -	ls = lock_stat_findnew(addr, name);
> +	ls = lock_stat_findnew(addr, name, 0);
>  	if (!ls)
>  		return -ENOMEM;
>  
> @@ -696,7 +699,7 @@ static int report_lock_acquired_event(struct evsel *evsel,
>  	if (show_thread_stats)
>  		addr = sample->tid;
>  
> -	ls = lock_stat_findnew(addr, name);
> +	ls = lock_stat_findnew(addr, name, 0);
>  	if (!ls)
>  		return -ENOMEM;
>  
> @@ -758,7 +761,7 @@ static int report_lock_contended_event(struct evsel *evsel,
>  	if (show_thread_stats)
>  		addr = sample->tid;
>  
> -	ls = lock_stat_findnew(addr, name);
> +	ls = lock_stat_findnew(addr, name, 0);
>  	if (!ls)
>  		return -ENOMEM;
>  
> @@ -813,7 +816,7 @@ static int report_lock_release_event(struct evsel *evsel,
>  	if (show_thread_stats)
>  		addr = sample->tid;
>  
> -	ls = lock_stat_findnew(addr, name);
> +	ls = lock_stat_findnew(addr, name, 0);
>  	if (!ls)
>  		return -ENOMEM;
>  
> @@ -985,11 +988,12 @@ static int report_lock_contention_begin_event(struct evsel *evsel,
>  	if (!ls) {
>  		char buf[128];
>  		const char *caller = buf;
> +		unsigned int flags = evsel__intval(evsel, sample, "flags");
>  
>  		if (lock_contention_caller(evsel, sample, buf, sizeof(buf)) < 0)
>  			caller = "Unknown";
>  
> -		ls = lock_stat_findnew(addr, caller);
> +		ls = lock_stat_findnew(addr, caller, flags);
>  		if (!ls)
>  			return -ENOMEM;
>  	}
> -- 
> 2.37.1.359.gd136c6c3e2-goog

-- 

- Arnaldo