perf top: Move lost events warning to helpline

mainline inclusion
from mainline-5.0-rc1
commit 254de74cd14a2e64323caeffe653de0f390a4e65
category: bugfix
bugzilla: NA
CVE: NA

-------------------------------------------------
We can't display the UI box saying that we are slow in the reader
thread.  That will make 'perf top' even slower and the user even more
angry ;-)

Move the UI box message from the reader thread to the UI thread and
change it to a helpline, so there's no need to 'press any key'.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/n/tip-x4k0iuw7tt6mywsaguq6jfwu@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NChunmei Xu <xuchunmei@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

tools/perf/builtin-top.c

@@ -553,8 +553,6 @@ static void perf_top__sort_new_samples(void *arg)
 	struct perf_evsel *evsel = t->sym_evsel;
 	struct hists *hists;
 
-	perf_top__reset_sample_counters(t);
-
 	if (t->evlist->selected != NULL)
 		t->sym_evsel = t->evlist->selected;
 
@@ -571,6 +569,11 @@ static void perf_top__sort_new_samples(void *arg)
 
 	hists__collapse_resort(hists, NULL);
 	perf_evsel__output_resort(evsel, NULL);
+
+	if (t->lost)
+		pr_warning("Too slow to read ring buffer (change period (-c/-F) or limit CPUs (-C)\n");
+
+	perf_top__reset_sample_counters(t);
 }
 
 static void *display_thread_tui(void *arg)
@@ -908,10 +911,8 @@ static void perf_top__mmap_read(struct perf_top *top)
 {
 	bool overwrite = top->record_opts.overwrite;
 	struct perf_evlist *evlist = top->evlist;
-	unsigned long long start, end;
 	int i;
 
-	start = rdclock();
 	if (overwrite)
 		perf_evlist__toggle_bkw_mmap(evlist, BKW_MMAP_DATA_PENDING);
 
@@ -922,13 +923,6 @@ static void perf_top__mmap_read(struct perf_top *top)
 		perf_evlist__toggle_bkw_mmap(evlist, BKW_MMAP_EMPTY);
 		perf_evlist__toggle_bkw_mmap(evlist, BKW_MMAP_RUNNING);
 	}
-	end = rdclock();
-
-	if ((end - start) > (unsigned long long)top->delay_secs * NSEC_PER_SEC)
-		ui__warning("Too slow to read ring buffer.\n"
-			    "Please try increasing the period (-c) or\n"
-			    "decreasing the freq (-F) or\n"
-			    "limiting the number of CPUs (-C)\n");
 }
 
 /*