Merge remote-tracking branch 'remotes/ericb/tags/pull-qapi-2018-03-12-v4' into staging

qapi patches for 2018-03-12, 2.12 softfreeze

- Marc-André Lureau: 0/4 qapi: generate a literal qobject for introspection
- Max Reitz: 0/7 block: Handle null backing link
- Daniel P. Berrange: chardev: tcp: postpone TLS work until machine done
- Peter Xu: 00/23 QMP: out-of-band (OOB) execution support
- Vladimir Sementsov-Ogievskiy: 0/2 block latency histogram
- Eric Blake: qapi: Pass '-u' when doing non-silent diff

# gpg: Signature made Mon 19 Mar 2018 19:59:04 GMT
# gpg:                using RSA key A7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-qapi-2018-03-12-v4: (38 commits)
  qapi: Pass '-u' when doing non-silent diff
  qapi: add block latency histogram interface
  block/accounting: introduce latency histogram
  tests: qmp-test: add oob test
  tests: qmp-test: verify command batching
  qmp: add command "x-oob-test"
  monitor: enable IO thread for (qmp & !mux) typed
  qmp: isolate responses into io thread
  qmp: support out-of-band (oob) execution
  qapi: introduce new cmd option "allow-oob"
  monitor: send event when command queue full
  qmp: add new event "command-dropped"
  monitor: separate QMP parser and dispatcher
  monitor: let suspend/resume work even with QMPs
  monitor: let suspend_cnt be thread safe
  monitor: introduce monitor_qmp_respond()
  qmp: introduce QMPCapability
  monitor: allow using IO thread for parsing
  monitor: let mon_list be tail queue
  monitor: unify global init
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 91 insertions, 0 deletions

diff --git a/block/accounting.c b/block/accounting.c
index 87ef5bbfaa..70a3d9a426 100644
--- a/block/accounting.c
+++ b/block/accounting.c
@@ -94,6 +94,94 @@ void block_acct_start(BlockAcctStats *stats, BlockAcctCookie *cookie,
     cookie->type = type;
 }
 
+/* block_latency_histogram_compare_func:
+ * Compare @key with interval [@it[0], @it[1]).
+ * Return: -1 if @key < @it[0]
+ *          0 if @key in [@it[0], @it[1])
+ *         +1 if @key >= @it[1]
+ */
+static int block_latency_histogram_compare_func(const void *key, const void *it)
+{
+    uint64_t k = *(uint64_t *)key;
+    uint64_t a = ((uint64_t *)it)[0];
+    uint64_t b = ((uint64_t *)it)[1];
+
+    return k < a ? -1 : (k < b ? 0 : 1);
+}
+
+static void block_latency_histogram_account(BlockLatencyHistogram *hist,
+                                            int64_t latency_ns)
+{
+    uint64_t *pos;
+
+    if (hist->bins == NULL) {
+        /* histogram disabled */
+        return;
+    }
+
+
+    if (latency_ns < hist->boundaries[0]) {
+        hist->bins[0]++;
+        return;
+    }
+
+    if (latency_ns >= hist->boundaries[hist->nbins - 2]) {
+        hist->bins[hist->nbins - 1]++;
+        return;
+    }
+
+    pos = bsearch(&latency_ns, hist->boundaries, hist->nbins - 2,
+                  sizeof(hist->boundaries[0]),
+                  block_latency_histogram_compare_func);
+    assert(pos != NULL);
+
+    hist->bins[pos - hist->boundaries + 1]++;
+}
+
+int block_latency_histogram_set(BlockAcctStats *stats, enum BlockAcctType type,
+                                uint64List *boundaries)
+{
+    BlockLatencyHistogram *hist = &stats->latency_histogram[type];
+    uint64List *entry;
+    uint64_t *ptr;
+    uint64_t prev = 0;
+    int new_nbins = 1;
+
+    for (entry = boundaries; entry; entry = entry->next) {
+        if (entry->value <= prev) {
+            return -EINVAL;
+        }
+        new_nbins++;
+        prev = entry->value;
+    }
+
+    hist->nbins = new_nbins;
+    g_free(hist->boundaries);
+    hist->boundaries = g_new(uint64_t, hist->nbins - 1);
+    for (entry = boundaries, ptr = hist->boundaries; entry;
+         entry = entry->next, ptr++)
+    {
+        *ptr = entry->value;
+    }
+
+    g_free(hist->bins);
+    hist->bins = g_new0(uint64_t, hist->nbins);
+
+    return 0;
+}
+
+void block_latency_histograms_clear(BlockAcctStats *stats)
+{
+    int i;
+
+    for (i = 0; i < BLOCK_MAX_IOTYPE; i++) {
+        BlockLatencyHistogram *hist = &stats->latency_histogram[i];
+        g_free(hist->bins);
+        g_free(hist->boundaries);
+        memset(hist, 0, sizeof(*hist));
+    }
+}
+
 static void block_account_one_io(BlockAcctStats *stats, BlockAcctCookie *cookie,
                                  bool failed)
 {
@@ -116,6 +204,9 @@ static void block_account_one_io(BlockAcctStats *stats, BlockAcctCookie *cookie,
         stats->nr_ops[cookie->type]++;
     }
 
+    block_latency_histogram_account(&stats->latency_histogram[cookie->type],
+                                    latency_ns);
+
     if (!failed || stats->account_failed) {
         stats->total_time_ns[cookie->type] += latency_ns;
         stats->last_access_time_ns = time_ns;