mmc: mmc_test: test to measure how sg_len affect performance

Add a test that measures how the mmc bandwidth depends on the numbers of
sg elements in the sg list. The transfer size if fixed and sg length goes
from a few up to 512. The purpose is to measure overhead caused by
multiple sg elements.
Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Venkatraman S <svenkatr@ti.com>
Tested-by: Sourav Poddar <sourav.poddar@ti.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/card/mmc_test.c

@@ -155,6 +155,7 @@ enum mmc_test_prep_media {
 };
 
 struct mmc_test_multiple_rw {
+	unsigned int *sg_len;
 	unsigned int *bs;
 	unsigned int len;
 	unsigned int size;
@@ -387,21 +388,26 @@ static struct mmc_test_mem *mmc_test_alloc_mem(unsigned long min_sz,
  * Map memory into a scatterlist.  Optionally allow the same memory to be
  * mapped more than once.
  */
-static int mmc_test_map_sg(struct mmc_test_mem *mem, unsigned long sz,
+static int mmc_test_map_sg(struct mmc_test_mem *mem, unsigned long size,
 			   struct scatterlist *sglist, int repeat,
 			   unsigned int max_segs, unsigned int max_seg_sz,
-			   unsigned int *sg_len)
+			   unsigned int *sg_len, int min_sg_len)
 {
 	struct scatterlist *sg = NULL;
 	unsigned int i;
+	unsigned long sz = size;
 
 	sg_init_table(sglist, max_segs);
+	if (min_sg_len > max_segs)
+		min_sg_len = max_segs;
 
 	*sg_len = 0;
 	do {
 		for (i = 0; i < mem->cnt; i++) {
 			unsigned long len = PAGE_SIZE << mem->arr[i].order;
 
+			if (min_sg_len && (size / min_sg_len < len))
+				len = ALIGN(size / min_sg_len, 512);
 			if (len > sz)
 				len = sz;
 			if (len > max_seg_sz)
@@ -574,11 +580,12 @@ static void mmc_test_print_avg_rate(struct mmc_test_card *test, uint64_t bytes,
 
 	printk(KERN_INFO "%s: Transfer of %u x %u sectors (%u x %u%s KiB) took "
 			 "%lu.%09lu seconds (%u kB/s, %u KiB/s, "
-			 "%u.%02u IOPS)\n",
+			 "%u.%02u IOPS, sg_len %d)\n",
 			 mmc_hostname(test->card->host), count, sectors, count,
 			 sectors >> 1, (sectors & 1 ? ".5" : ""),
 			 (unsigned long)ts.tv_sec, (unsigned long)ts.tv_nsec,
-			 rate / 1000, rate / 1024, iops / 100, iops % 100);
+			 rate / 1000, rate / 1024, iops / 100, iops % 100,
+			 test->area.sg_len);
 
 	mmc_test_save_transfer_result(test, count, sectors, ts, rate, iops);
 }
@@ -1412,7 +1419,7 @@ static int mmc_test_no_highmem(struct mmc_test_card *test)
  * Map sz bytes so that it can be transferred.
  */
 static int mmc_test_area_map(struct mmc_test_card *test, unsigned long sz,
-			     int max_scatter)
+			     int max_scatter, int min_sg_len)
 {
 	struct mmc_test_area *t = &test->area;
 	int err;
@@ -1425,7 +1432,7 @@ static int mmc_test_area_map(struct mmc_test_card *test, unsigned long sz,
 				       &t->sg_len);
 	} else {
 		err = mmc_test_map_sg(t->mem, sz, t->sg, 1, t->max_segs,
-				      t->max_seg_sz, &t->sg_len);
+				      t->max_seg_sz, &t->sg_len, min_sg_len);
 	}
 	if (err)
 		printk(KERN_INFO "%s: Failed to map sg list\n",
@@ -1451,7 +1458,7 @@ static int mmc_test_area_transfer(struct mmc_test_card *test,
 static int mmc_test_area_io_seq(struct mmc_test_card *test, unsigned long sz,
 				unsigned int dev_addr, int write,
 				int max_scatter, int timed, int count,
-				bool nonblock)
+				bool nonblock, int min_sg_len)
 {
 	struct timespec ts1, ts2;
 	int ret = 0;
@@ -1474,7 +1481,7 @@ static int mmc_test_area_io_seq(struct mmc_test_card *test, unsigned long sz,
 			sz = max_tfr;
 	}
 
-	ret = mmc_test_area_map(test, sz, max_scatter);
+	ret = mmc_test_area_map(test, sz, max_scatter, min_sg_len);
 	if (ret)
 		return ret;
 
@@ -1506,7 +1513,7 @@ static int mmc_test_area_io(struct mmc_test_card *test, unsigned long sz,
 			    int timed)
 {
 	return mmc_test_area_io_seq(test, sz, dev_addr, write, max_scatter,
-				    timed, 1, false);
+				    timed, 1, false, 0);
 }
 
 /*
@@ -2084,7 +2091,8 @@ static int mmc_test_large_seq_write_perf(struct mmc_test_card *test)
 
 static int mmc_test_rw_multiple(struct mmc_test_card *test,
 				struct mmc_test_multiple_rw *tdata,
-				unsigned int reqsize, unsigned int size)
+				unsigned int reqsize, unsigned int size,
+				int min_sg_len)
 {
 	unsigned int dev_addr;
 	struct mmc_test_area *t = &test->area;
@@ -2121,7 +2129,7 @@ static int mmc_test_rw_multiple(struct mmc_test_card *test,
 	/* Run test */
 	ret = mmc_test_area_io_seq(test, reqsize, dev_addr,
 				   tdata->do_write, 0, 1, size / reqsize,
-				   tdata->do_nonblock_req);
+				   tdata->do_nonblock_req, min_sg_len);
 	if (ret)
 		goto err;
 
@@ -2146,7 +2154,22 @@ static int mmc_test_rw_multiple_size(struct mmc_test_card *test,
 	}
 
 	for (i = 0 ; i < rw->len && ret == 0; i++) {
-		ret = mmc_test_rw_multiple(test, rw, rw->bs[i], rw->size);
+		ret = mmc_test_rw_multiple(test, rw, rw->bs[i], rw->size, 0);
+		if (ret)
+			break;
+	}
+	return ret;
+}
+
+static int mmc_test_rw_multiple_sg_len(struct mmc_test_card *test,
+				       struct mmc_test_multiple_rw *rw)
+{
+	int ret = 0;
+	int i;
+
+	for (i = 0 ; i < rw->len && ret == 0; i++) {
+		ret = mmc_test_rw_multiple(test, rw, 512*1024, rw->size,
+					   rw->sg_len[i]);
 		if (ret)
 			break;
 	}
@@ -2229,6 +2252,82 @@ static int mmc_test_profile_mult_read_nonblock_perf(struct mmc_test_card *test)
 	return mmc_test_rw_multiple_size(test, &test_data);
 }
 
+/*
+ * Multiple blocking write 1 to 512 sg elements
+ */
+static int mmc_test_profile_sglen_wr_blocking_perf(struct mmc_test_card *test)
+{
+	unsigned int sg_len[] = {1, 1 << 3, 1 << 4, 1 << 5, 1 << 6,
+				 1 << 7, 1 << 8, 1 << 9};
+	struct mmc_test_multiple_rw test_data = {
+		.sg_len = sg_len,
+		.size = TEST_AREA_MAX_SIZE,
+		.len = ARRAY_SIZE(sg_len),
+		.do_write = true,
+		.do_nonblock_req = false,
+		.prepare = MMC_TEST_PREP_ERASE,
+	};
+
+	return mmc_test_rw_multiple_sg_len(test, &test_data);
+};
+
+/*
+ * Multiple non-blocking write 1 to 512 sg elements
+ */
+static int mmc_test_profile_sglen_wr_nonblock_perf(struct mmc_test_card *test)
+{
+	unsigned int sg_len[] = {1, 1 << 3, 1 << 4, 1 << 5, 1 << 6,
+				 1 << 7, 1 << 8, 1 << 9};
+	struct mmc_test_multiple_rw test_data = {
+		.sg_len = sg_len,
+		.size = TEST_AREA_MAX_SIZE,
+		.len = ARRAY_SIZE(sg_len),
+		.do_write = true,
+		.do_nonblock_req = true,
+		.prepare = MMC_TEST_PREP_ERASE,
+	};
+
+	return mmc_test_rw_multiple_sg_len(test, &test_data);
+}
+
+/*
+ * Multiple blocking read 1 to 512 sg elements
+ */
+static int mmc_test_profile_sglen_r_blocking_perf(struct mmc_test_card *test)
+{
+	unsigned int sg_len[] = {1, 1 << 3, 1 << 4, 1 << 5, 1 << 6,
+				 1 << 7, 1 << 8, 1 << 9};
+	struct mmc_test_multiple_rw test_data = {
+		.sg_len = sg_len,
+		.size = TEST_AREA_MAX_SIZE,
+		.len = ARRAY_SIZE(sg_len),
+		.do_write = false,
+		.do_nonblock_req = false,
+		.prepare = MMC_TEST_PREP_NONE,
+	};
+
+	return mmc_test_rw_multiple_sg_len(test, &test_data);
+}
+
+/*
+ * Multiple non-blocking read 1 to 512 sg elements
+ */
+static int mmc_test_profile_sglen_r_nonblock_perf(struct mmc_test_card *test)
+{
+	unsigned int sg_len[] = {1, 1 << 3, 1 << 4, 1 << 5, 1 << 6,
+				 1 << 7, 1 << 8, 1 << 9};
+	struct mmc_test_multiple_rw test_data = {
+		.sg_len = sg_len,
+		.size = TEST_AREA_MAX_SIZE,
+		.len = ARRAY_SIZE(sg_len),
+		.do_write = false,
+		.do_nonblock_req = true,
+		.prepare = MMC_TEST_PREP_NONE,
+	};
+
+	return mmc_test_rw_multiple_sg_len(test, &test_data);
+}
+
 static const struct mmc_test_case mmc_test_cases[] = {
 	{
 		.name = "Basic write (no data verification)",
@@ -2523,6 +2622,34 @@ static const struct mmc_test_case mmc_test_cases[] = {
 		.run = mmc_test_profile_mult_read_nonblock_perf,
 		.cleanup = mmc_test_area_cleanup,
 	},
+
+	{
+		.name = "Write performance blocking req 1 to 512 sg elems",
+		.prepare = mmc_test_area_prepare,
+		.run = mmc_test_profile_sglen_wr_blocking_perf,
+		.cleanup = mmc_test_area_cleanup,
+	},
+
+	{
+		.name = "Write performance non-blocking req 1 to 512 sg elems",
+		.prepare = mmc_test_area_prepare,
+		.run = mmc_test_profile_sglen_wr_nonblock_perf,
+		.cleanup = mmc_test_area_cleanup,
+	},
+
+	{
+		.name = "Read performance blocking req 1 to 512 sg elems",
+		.prepare = mmc_test_area_prepare,
+		.run = mmc_test_profile_sglen_r_blocking_perf,
+		.cleanup = mmc_test_area_cleanup,
+	},
+
+	{
+		.name = "Read performance non-blocking req 1 to 512 sg elems",
+		.prepare = mmc_test_area_prepare,
+		.run = mmc_test_profile_sglen_r_nonblock_perf,
+		.cleanup = mmc_test_area_cleanup,
+	},
 };
 
 static DEFINE_MUTEX(mmc_test_lock);