[PATCH 34/46] perf tools: Squash overwrite setting into channel

Wang Nan
2016-02-26T09:34:35Z

Make 'overwrite' a channel configuration other than a evlist global
option. With this setting an evlist can have two channels, one is
normal channel, another is overwritable channel.
perf_evlist__channel_for_evsel() ensures events with 'overwrite'
configuration inserted to overwritable channel.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: He Kuang <hekuang@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
tools/perf/builtin-record.c | 2 +-
tools/perf/util/evlist.c | 42 +++++++++++++++++++++++++++---------------
tools/perf/util/evlist.h | 5 ++---
tools/perf/util/evsel.h | 1 +
4 files changed, 31 insertions(+), 19 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index d48065f..92eccf1 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -358,7 +358,7 @@ try_again:
}

perf_evlist__channel_reset(evlist);
- if (perf_evlist__mmap_ex(evlist, opts->mmap_pages, false,
+ if (perf_evlist__mmap_ex(evlist, opts->mmap_pages,
opts->auxtrace_mmap_pages,
opts->auxtrace_snapshot_mode) < 0) {
if (errno == EPERM) {
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index c4e3185..067c89d 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -731,7 +731,7 @@ union perf_event *perf_evlist__mmap_read_ex(struct perf_evlist *evlist,
return NULL;

head = perf_mmap__read_head(md);
- if (evlist->overwrite) {
+ if (perf_evlist__channel_check(evlist, channel, RDONLY)) {
/*
* If we're further behind than half the buffer, there's a chance
* the writer will bite our tail and mess up the samples under us.
@@ -820,7 +820,7 @@ void perf_evlist__mmap_consume_ex(struct perf_evlist *evlist,
return;
}

- if (!evlist->overwrite) {
+ if (!perf_evlist__channel_check(evlist, channel, RDONLY)) {
u64 old = md->prev;

perf_mmap__write_tail(md, old);
@@ -918,7 +918,6 @@ static int perf_evlist__alloc_mmap(struct perf_evlist *evlist)
}

struct mmap_params {
- int prot;
int mask;
struct auxtrace_mmap_params auxtrace_mp;
};
@@ -926,6 +925,15 @@ struct mmap_params {
static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
struct mmap_params *mp, int fd)
{
+ int channel = perf_evlist__idx_channel(evlist, idx);
+ int prot = PROT_READ;
+
+ if (channel < 0)
+ return -1;
+
+ if (!perf_evlist__channel_check(evlist, channel, RDONLY))
+ prot |= PROT_WRITE;
+
/*
* The last one will be done at perf_evlist__mmap_consume(), so that we
* make sure we don't prevent tools from consuming every last event in
@@ -942,7 +950,7 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
atomic_set(&evlist->mmap[idx].refcnt, 2);
evlist->mmap[idx].prev = 0;
evlist->mmap[idx].mask = mp->mask;
- evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, mp->prot,
+ evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, prot,
MAP_SHARED, fd, 0);
if (evlist->mmap[idx].base == MAP_FAILED) {
pr_debug2("failed to mmap perf event ring buffer, error %d\n",
@@ -959,9 +967,13 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
}

static unsigned long
-perf_evlist__channel_for_evsel(struct perf_evsel *evsel __maybe_unused)
+perf_evlist__channel_for_evsel(struct perf_evsel *evsel)
{
- return 0;
+ unsigned long flag = 0;
+
+ if (evsel->overwrite)
+ flag |= PERF_EVLIST__CHANNEL_RDONLY;
+ return flag;
}

static int
@@ -1211,11 +1223,10 @@ int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
* perf_evlist__mmap_ex - Create mmaps to receive events.
* @evlist: list of events
* @pages: map length in pages
- * @overwrite: overwrite older events?
* @auxtrace_pages - auxtrace map length in pages
* @auxtrace_overwrite - overwrite older auxtrace data?
*
- * If @overwrite is %false the user needs to signal event consumption using
+ * For writable channel, the user needs to signal event consumption using
* perf_mmap__write_tail(). Using perf_evlist__mmap_read() does this
* automatically.
*
@@ -1225,16 +1236,13 @@ int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
* Return: %0 on success, negative error code otherwise.
*/
int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
- bool overwrite, unsigned int auxtrace_pages,
- bool auxtrace_overwrite)
+ unsigned int auxtrace_pages, bool auxtrace_overwrite)
{
int err;
struct perf_evsel *evsel;
const struct cpu_map *cpus = evlist->cpus;
const struct thread_map *threads = evlist->threads;
- struct mmap_params mp = {
- .prot = PROT_READ | (overwrite ? 0 : PROT_WRITE),
- };
+ struct mmap_params mp;

err = perf_evlist__channel_complete(evlist);
if (err)
@@ -1246,7 +1254,6 @@ int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
if (evlist->pollfd.entries == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
return -ENOMEM;

- evlist->overwrite = overwrite;
evlist->mmap_len = perf_evlist__mmap_size(pages);
pr_debug("mmap size %zuB\n", evlist->mmap_len);
mp.mask = evlist->mmap_len - page_size - 1;
@@ -1270,8 +1277,13 @@ int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
bool overwrite)
{
+ struct perf_evsel *evsel;
+
perf_evlist__channel_reset(evlist);
- return perf_evlist__mmap_ex(evlist, pages, overwrite, 0, false);
+ evlist__for_each(evlist, evsel)
+ evsel->overwrite = overwrite;
+
+ return perf_evlist__mmap_ex(evlist, pages, 0, false);
}

int perf_evlist__create_maps(struct perf_evlist *evlist, struct target *target)
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index b652587..21a8b85 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -23,6 +23,7 @@ struct record_opts;
#define PERF_EVLIST__NR_CHANNELS 2
enum perf_evlist_mmap_flag {
PERF_EVLIST__CHANNEL_ENABLED = 1,
+ PERF_EVLIST__CHANNEL_RDONLY = 2,
};

/**
@@ -45,7 +46,6 @@ struct perf_evlist {
int nr_entries;
int nr_groups;
int nr_mmaps;
- bool overwrite;
bool enabled;
bool has_user_cpus;
size_t mmap_len;
@@ -203,8 +203,7 @@ int perf_evlist__parse_mmap_pages(const struct option *opt,
int unset);

int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
- bool overwrite, unsigned int auxtrace_pages,
- bool auxtrace_overwrite);
+ unsigned int auxtrace_pages, bool auxtrace_overwrite);
int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
bool overwrite);
void perf_evlist__munmap(struct perf_evlist *evlist);
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index efad78f..03c70e5 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -114,6 +114,7 @@ struct perf_evsel {
bool tracking;
bool per_pkg;
bool precise_max;
+ bool overwrite;
/* parse modifier helper */
int exclude_GH;
int nr_members;
--
1.8.3.4