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Date:   Mon, 25 Jan 2021 10:45:54 +0100
From:   Jiri Olsa <jolsa@redhat.com>
To:     "Jin, Yao" <yao.jin@linux.intel.com>
Cc:     acme@kernel.org, jolsa@kernel.org, peterz@infradead.org,
        mingo@redhat.com, alexander.shishkin@linux.intel.com,
        Linux-kernel@vger.kernel.org, ak@linux.intel.com,
        kan.liang@intel.com, yao.jin@intel.com, ying.huang@intel.com
Subject: Re: [PATCH v7] perf stat: Fix wrong skipping for per-die aggregation
Message-ID: <20210125094554.GB245791@krava>
References: <20210118040521.31003-1-yao.jin@linux.intel.com>
 <20210120220735.GE1798087@krava>
 <dd75cc3f-9440-c33b-cea3-529134c33e80@linux.intel.com>
 <20210123225709.GB138414@krava>
 <de88878b-b184-b1a2-ad91-1069d81c4e53@linux.intel.com>
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On Mon, Jan 25, 2021 at 01:47:54PM +0800, Jin, Yao wrote:
> Hi Jiri,
> 
> On 1/24/2021 6:57 AM, Jiri Olsa wrote:
> > On Thu, Jan 21, 2021 at 12:21:36PM +0800, Jin, Yao wrote:
> > 
> > sNIP
> > 
> > > mask = hashmap__new(pkg_id_hash, pkg_id_equal, NULL);
> > > d = cpu_map__get_die(cpus, cpu, NULL).die;
> > > key = (size_t)d << KEY_SHIFT | s;	/* s is socket id */
> > > if (hashmap__find(mask, (void *)key, NULL))
> > > 	*skip = true;
> > > else
> > > 	ret = hashmap__add(mask, (void *)key, (void *)1);
> > > 
> > > If we use 'unsigned long' to replace 'size_t', it reports the build error for 32 bits:
> > > 
> > > stat.c:320:23: warning: passing argument 1 of ‘hashmap__new’ from
> > > incompatible pointer type [-Wincompatible-pointer-types]
> > >     mask = hashmap__new(pkg_id_hash, pkg_id_equal, NULL);
> > >                         ^~~~~~~~~~~
> > > In file included from stat.c:16:
> > > hashmap.h:75:17: note: expected ‘hashmap_hash_fn’ {aka ‘unsigned int
> > > (*)(const void *, void *)’} but argument is of type ‘long unsigned int
> > > (*)(const void *, void *)’
> > > 
> > > If we use "unsigned int", it's not good for 64 bits. So I still use 'size_t' in this patch.
> > > 
> > > Any comments for this idea (using conditional compilation)?
> > 
> > isn't it simpler to allocate the key then? like below
> > (just compile tested)
> > 
> > jirka
> > 
> 
> Hmm, Each method has advantages and disadvantages.
> 
> My method uses conditional compilation but it looks a bit complicated. The
> advantage is it doesn't need to allocate the memory for key.
> 
> If you need me to post v8, I'd love to.
> 
> Anyway, either method is fine for me. :)

I believe that the less ifdefs te better, if you could squash this
change with your patch and send it, that'd be great

SNIP

> > +	return *key & 0xffffffff;
> >   }
> > -static bool pkg_id_equal(const void *key1, const void *key2,
> > +static bool pkg_id_equal(const void *__key1, const void *__key2,
> >   			 void *ctx __maybe_unused)
> >   {
> > -	return (size_t)key1 == (size_t)key2;
> > +	uint64_t *key1 = (uint64_t*) __key1;
> > +	uint64_t *key2 = (uint64_t*) __key2;
> > +
> > +	return *key1 == *key2;
> >   }
> >   static int check_per_pkg(struct evsel *counter,
> > @@ -297,7 +309,7 @@ static int check_per_pkg(struct evsel *counter,
> >   	struct hashmap *mask = counter->per_pkg_mask;
> >   	struct perf_cpu_map *cpus = evsel__cpus(counter);
> >   	int s, d, ret = 0;
> > -	size_t key;
> > +	uint64_t *key;
> >   	*skip = false;
> > @@ -338,7 +350,11 @@ static int check_per_pkg(struct evsel *counter,
> >   	if (d < 0)
> >   		return -1;
> > -	key = (size_t)d << 16 | s;
> > +	key = malloc(sizeof(*key));
> > +	if (!key)
> > +		return -ENOMEM;
> > +
> > +	*key = (size_t)d << 32 | s;
> 
> Should be "*key = (uint64_t)d << 32 | s;"?

yes, I missed this bit

thanks,
jirka