[Qemu-devel] [PATCH 2/3] block/accounting: introduce block size histogram

[zhenwei pi <pizhenwei@bytedance.com>]

Introduce block size histogram statics for block devices.

For read/write/flush operation type, the block size region
[0, +inf) is divided into subregions by several points.
It works like block latency histogram.

Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
---
 block/accounting.c         | 24 ++++++++++++++++++++++++
 include/block/accounting.h |  4 ++++
 2 files changed, 28 insertions(+)

diff --git a/block/accounting.c b/block/accounting.c
index bb8148b6b1..94d5aa292e 100644
--- a/block/accounting.c
+++ b/block/accounting.c
@@ -187,6 +187,27 @@ void block_latency_histograms_clear(BlockAcctStats *stats)
     }
 }
 
+int block_size_histogram_set(BlockAcctStats *stats, enum BlockAcctType type,
+                                uint64List *boundaries)
+{
+    BlockHistogram *hist = &stats->size_histogram[type];
+
+    return block_histogram_set(hist, boundaries);
+}
+
+void block_size_histograms_clear(BlockAcctStats *stats)
+{
+    int i;
+
+    for (i = 0; i < BLOCK_MAX_IOTYPE; i++) {
+        BlockHistogram *hist = &stats->size_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)
 {
@@ -211,6 +232,9 @@ static void block_account_one_io(BlockAcctStats *stats, BlockAcctCookie *cookie,
 
     block_histogram_account(&stats->latency_histogram[cookie->type],
                                     latency_ns);
+    block_histogram_account(&stats->size_histogram[cookie->type],
+                                    cookie->bytes);
+
 
     if (!failed || stats->account_failed) {
         stats->total_time_ns[cookie->type] += latency_ns;
diff --git a/include/block/accounting.h b/include/block/accounting.h
index 270fddb69c..49d3a78f48 100644
--- a/include/block/accounting.h
+++ b/include/block/accounting.h
@@ -89,6 +89,7 @@ struct BlockAcctStats {
     bool account_invalid;
     bool account_failed;
     BlockHistogram latency_histogram[BLOCK_MAX_IOTYPE];
+    BlockHistogram size_histogram[BLOCK_MAX_IOTYPE];
 };
 
 typedef struct BlockAcctCookie {
@@ -117,5 +118,8 @@ double block_acct_queue_depth(BlockAcctTimedStats *stats,
 int block_latency_histogram_set(BlockAcctStats *stats, enum BlockAcctType type,
                                 uint64List *boundaries);
 void block_latency_histograms_clear(BlockAcctStats *stats);
+int block_size_histogram_set(BlockAcctStats *stats, enum BlockAcctType type,
+                                uint64List *boundaries);
+void block_size_histograms_clear(BlockAcctStats *stats);
 
 #endif
-- 
2.11.0