From 96563db9995c5cebdce526f2bf97923153d4456b Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Fri, 14 Dec 2018 08:32:01 -0700
Subject: [PATCH] Add cache hit stats

With the aioring engine, we can get notified if a buffered read was
a cache hit or if it hit media. Add that to the output stats for
normal and json output.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 client.c          |  3 +++
 engines/aioring.c | 15 +++++++++++++++
 server.c          |  3 +++
 server.h          |  2 +-
 stat.c            | 31 +++++++++++++++++++++++++++----
 stat.h            |  3 +++
 6 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/client.c b/client.c
index c8850440..480425f6 100644
--- a/client.c
+++ b/client.c
@@ -1039,6 +1039,9 @@ static void convert_ts(struct thread_stat *dst, struct thread_stat *src)
 			dst->ss_bw_data[i] = le64_to_cpu(src->ss_bw_data[i]);
 		}
 	}
+
+	dst->cachehit		= le64_to_cpu(src->cachehit);
+	dst->cachemiss		= le64_to_cpu(src->cachemiss);
 }
 
 static void convert_gs(struct group_run_stats *dst, struct group_run_stats *src)
diff --git a/engines/aioring.c b/engines/aioring.c
index 46469dbf..ce9a2aac 100644
--- a/engines/aioring.c
+++ b/engines/aioring.c
@@ -63,6 +63,8 @@ typedef uint16_t u16;
 
 #define IORING_SQ_NEED_WAKEUP	(1 << 0)
 
+#define IOEV_RES2_CACHEHIT	(1 << 0)
+
 struct aio_sq_ring {
 	union {
 		struct {
@@ -103,6 +105,9 @@ struct aioring_data {
 
 	int queued;
 	int cq_ring_off;
+
+	uint64_t cachehit;
+	uint64_t cachemiss;
 };
 
 struct aioring_options {
@@ -241,6 +246,13 @@ static struct io_u *fio_aioring_event(struct thread_data *td, int event)
 	} else
 		io_u->error = 0;
 
+	if (io_u->ddir == DDIR_READ) {
+		if (ev->res2 & IOEV_RES2_CACHEHIT)
+			ld->cachehit++;
+		else
+			ld->cachemiss++;
+	}
+
 	return io_u;
 }
 
@@ -431,6 +443,9 @@ static void fio_aioring_cleanup(struct thread_data *td)
 	struct aioring_data *ld = td->io_ops_data;
 
 	if (ld) {
+		td->ts.cachehit += ld->cachehit;
+		td->ts.cachemiss += ld->cachemiss;
+
 		/* Bump depth to match init depth */
 		td->o.iodepth++;
 
diff --git a/server.c b/server.c
index 96e51819..2a337707 100644
--- a/server.c
+++ b/server.c
@@ -1563,6 +1563,9 @@ void fio_server_send_ts(struct thread_stat *ts, struct group_run_stats *rs)
 	p.ts.ss_deviation.u.i	= cpu_to_le64(fio_double_to_uint64(ts->ss_deviation.u.f));
 	p.ts.ss_criterion.u.i	= cpu_to_le64(fio_double_to_uint64(ts->ss_criterion.u.f));
 
+	p.ts.cachehit		= cpu_to_le64(ts->cachehit);
+	p.ts.cachemiss		= cpu_to_le64(ts->cachemiss);
+
 	convert_gs(&p.rs, rs);
 
 	dprint(FD_NET, "ts->ss_state = %d\n", ts->ss_state);
diff --git a/server.h b/server.h
index 371e51ea..abb23bad 100644
--- a/server.h
+++ b/server.h
@@ -48,7 +48,7 @@ struct fio_net_cmd_reply {
 };
 
 enum {
-	FIO_SERVER_VER			= 77,
+	FIO_SERVER_VER			= 78,
 
 	FIO_SERVER_MAX_FRAGMENT_PDU	= 1024,
 	FIO_SERVER_MAX_CMD_MB		= 2048,
diff --git a/stat.c b/stat.c
index 887509fe..ec75de24 100644
--- a/stat.c
+++ b/stat.c
@@ -419,7 +419,7 @@ static void show_ddir_status(struct group_run_stats *rs, struct thread_stat *ts,
 	unsigned long runt;
 	unsigned long long min, max, bw, iops;
 	double mean, dev;
-	char *io_p, *bw_p, *bw_p_alt, *iops_p, *zbd_w_st = NULL;
+	char *io_p, *bw_p, *bw_p_alt, *iops_p, *post_st = NULL;
 	int i2p;
 
 	if (ddir_sync(ddir)) {
@@ -451,15 +451,25 @@ static void show_ddir_status(struct group_run_stats *rs, struct thread_stat *ts,
 	iops = (1000 * (uint64_t)ts->total_io_u[ddir]) / runt;
 	iops_p = num2str(iops, ts->sig_figs, 1, 0, N2S_NONE);
 	if (ddir == DDIR_WRITE)
-		zbd_w_st = zbd_write_status(ts);
+		post_st = zbd_write_status(ts);
+	else if (ddir == DDIR_READ && ts->cachehit && ts->cachemiss) {
+		uint64_t total;
+		double hit;
+
+		total = ts->cachehit + ts->cachemiss;
+		hit = (double) ts->cachehit / (double) total;
+		hit *= 100.0;
+		if (asprintf(&post_st, "; Cachehit=%0.2f%%", hit) < 0)
+			post_st = NULL;
+	}
 
 	log_buf(out, "  %s: IOPS=%s, BW=%s (%s)(%s/%llumsec)%s\n",
 			rs->unified_rw_rep ? "mixed" : io_ddir_name(ddir),
 			iops_p, bw_p, bw_p_alt, io_p,
 			(unsigned long long) ts->runtime[ddir],
-			zbd_w_st ? : "");
+			post_st ? : "");
 
-	free(zbd_w_st);
+	free(post_st);
 	free(io_p);
 	free(bw_p);
 	free(bw_p_alt);
@@ -1153,6 +1163,16 @@ static void add_ddir_status_json(struct thread_stat *ts,
 	json_object_add_value_float(dir_object, "iops_stddev", dev);
 	json_object_add_value_int(dir_object, "iops_samples",
 				(&ts->iops_stat[ddir])->samples);
+
+	if (ts->cachehit + ts->cachemiss) {
+		uint64_t total;
+		double hit;
+
+		total = ts->cachehit + ts->cachemiss;
+		hit = (double) ts->cachehit / (double) total;
+		hit *= 100.0;
+		json_object_add_value_float(dir_object, "cachehit", hit);
+	}
 }
 
 static void show_thread_status_terse_all(struct thread_stat *ts,
@@ -1695,6 +1715,8 @@ void sum_thread_stats(struct thread_stat *dst, struct thread_stat *src,
 	dst->total_submit += src->total_submit;
 	dst->total_complete += src->total_complete;
 	dst->nr_zone_resets += src->nr_zone_resets;
+	dst->cachehit += src->cachehit;
+	dst->cachemiss += src->cachemiss;
 }
 
 void init_group_run_stat(struct group_run_stats *gs)
@@ -2376,6 +2398,7 @@ void reset_io_stats(struct thread_data *td)
 	ts->total_submit = 0;
 	ts->total_complete = 0;
 	ts->nr_zone_resets = 0;
+	ts->cachehit = ts->cachemiss = 0;
 }
 
 static void __add_stat_to_log(struct io_log *iolog, enum fio_ddir ddir,
diff --git a/stat.h b/stat.h
index b4ba71e3..e9551381 100644
--- a/stat.h
+++ b/stat.h
@@ -246,6 +246,9 @@ struct thread_stat {
 		uint64_t *ss_bw_data;
 		uint64_t pad5;
 	};
+
+	uint64_t cachehit;
+	uint64_t cachemiss;
 } __attribute__((packed));
 
 struct jobs_eta {
-- 
2.25.1