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authorWang Nan <wangnan0@huawei.com>2016-07-14 08:34:42 +0000
committerArnaldo Carvalho de Melo <acme@redhat.com>2016-07-15 17:27:49 -0300
commit54cc54decd79b2c92f4db06001b4b245f38181b7 (patch)
tree86a2268deb1222478ec35d4916767d32dd4830bc /tools/perf/util/evlist.c
parenta0c6f451f90204847ce5f91c3268d83a76bde1b6 (diff)
perf evlist: Setup backward mmap state machine
Introduce a bkw_mmap_state state machine to evlist: .________________(forbid)_____________. | V NOTREADY --(0)--> RUNNING --(1)--> DATA_PENDING --(2)--> EMPTY ^ ^ | ^ | | |__(forbid)____/ |___(forbid)___/| | | \_________________(3)_______________/ NOTREADY : Backward ring buffers are not ready RUNNING : Backward ring buffers are recording DATA_PENDING : We are required to collect data from backward ring buffers EMPTY : We have collected data from backward ring buffers. (0): Setup backward ring buffer (1): Pause ring buffers for reading (2): Read from ring buffers (3): Resume ring buffers for recording We can't avoid this complexity. Since we deliberately drop records from overwritable ring buffer, there's no way for us to check remaining from ring buffer itself (by checking head and old pointers). Therefore, we need DATA_PENDING and EMPTY state to help us recording what we have done to the ring buffer. In record__mmap_read_evlist(), drive this state machine from DATA_PENDING to EMPTY. In perf_evlist__mmap_per_evsel(), drive this state machine from NOTREADY to RUNNING when creating backward mmap. Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Nilay Vaish <nilayvaish@gmail.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1468485287-33422-11-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/evlist.c')
-rw-r--r--tools/perf/util/evlist.c62
1 files changed, 62 insertions, 0 deletions
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 5beb44faa71d..93ab66415f51 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -15,6 +15,7 @@
#include "evlist.h"
#include "evsel.h"
#include "debug.h"
+#include "asm/bug.h"
#include <unistd.h>
#include "parse-events.h"
@@ -44,6 +45,7 @@ void perf_evlist__init(struct perf_evlist *evlist, struct cpu_map *cpus,
perf_evlist__set_maps(evlist, cpus, threads);
fdarray__init(&evlist->pollfd, 64);
evlist->workload.pid = -1;
+ evlist->bkw_mmap_state = BKW_MMAP_NOTREADY;
}
struct perf_evlist *perf_evlist__new(void)
@@ -1068,6 +1070,8 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
if (!maps)
return -1;
evlist->backward_mmap = maps;
+ if (evlist->bkw_mmap_state == BKW_MMAP_NOTREADY)
+ perf_evlist__toggle_bkw_mmap(evlist, BKW_MMAP_RUNNING);
}
}
@@ -1972,3 +1976,61 @@ perf_evlist__find_evsel_by_str(struct perf_evlist *evlist,
return NULL;
}
+
+void perf_evlist__toggle_bkw_mmap(struct perf_evlist *evlist,
+ enum bkw_mmap_state state)
+{
+ enum bkw_mmap_state old_state = evlist->bkw_mmap_state;
+ enum action {
+ NONE,
+ PAUSE,
+ RESUME,
+ } action = NONE;
+
+ if (!evlist->backward_mmap)
+ return;
+
+ switch (old_state) {
+ case BKW_MMAP_NOTREADY: {
+ if (state != BKW_MMAP_RUNNING)
+ goto state_err;;
+ break;
+ }
+ case BKW_MMAP_RUNNING: {
+ if (state != BKW_MMAP_DATA_PENDING)
+ goto state_err;
+ action = PAUSE;
+ break;
+ }
+ case BKW_MMAP_DATA_PENDING: {
+ if (state != BKW_MMAP_EMPTY)
+ goto state_err;
+ break;
+ }
+ case BKW_MMAP_EMPTY: {
+ if (state != BKW_MMAP_RUNNING)
+ goto state_err;
+ action = RESUME;
+ break;
+ }
+ default:
+ WARN_ONCE(1, "Shouldn't get there\n");
+ }
+
+ evlist->bkw_mmap_state = state;
+
+ switch (action) {
+ case PAUSE:
+ perf_evlist__pause(evlist);
+ break;
+ case RESUME:
+ perf_evlist__resume(evlist);
+ break;
+ case NONE:
+ default:
+ break;
+ }
+
+state_err:
+ return;
+}