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authorKeith Busch <kbusch@kernel.org>2023-01-26 13:51:14 -0800
committerAndrew Morton <akpm@linux-foundation.org>2023-04-05 19:42:38 -0700
commitdef8574308edbc3bca821fb965e429a2fe5f4971 (patch)
tree415822a2abc80d0897b69c0c3e9b03a4981fa3a6
parent3c556d2425b04054e22045d4ef7d34f163b7a71a (diff)
dmapool: add alloc/free performance test
Patch series "dmapool enhancements", v4. Time spent in dma_pool alloc/free increases linearly with the number of pages backing the pool. We can reduce this to constant time with minor changes to how free pages are tracked. This patch (of 12): Provide a module that allocates and frees many blocks of various sizes and report how long it takes. This is intended to provide a consistent way to measure how changes to the dma_pool_alloc/free routines affect timing. Link: https://lkml.kernel.org/r/20230126215125.4069751-1-kbusch@meta.com Link: https://lkml.kernel.org/r/20230126215125.4069751-2-kbusch@meta.com Signed-off-by: Keith Busch <kbusch@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--mm/Kconfig9
-rw-r--r--mm/Makefile1
-rw-r--r--mm/dmapool_test.c147
3 files changed, 157 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index 4751031f3f05..ca98b2072df5 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -1100,6 +1100,15 @@ comment "GUP_TEST needs to have DEBUG_FS enabled"
config GUP_GET_PXX_LOW_HIGH
bool
+config DMAPOOL_TEST
+ tristate "Enable a module to run time tests on dma_pool"
+ depends on HAS_DMA
+ help
+ Provides a test module that will allocate and free many blocks of
+ various sizes and report how long it takes. This is intended to
+ provide a consistent way to measure how changes to the
+ dma_pool_alloc/free routines affect performance.
+
config ARCH_HAS_PTE_SPECIAL
bool
diff --git a/mm/Makefile b/mm/Makefile
index 8e105e5b3e29..3a08f5d7b178 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -103,6 +103,7 @@ obj-$(CONFIG_MEMCG) += swap_cgroup.o
endif
obj-$(CONFIG_CGROUP_HUGETLB) += hugetlb_cgroup.o
obj-$(CONFIG_GUP_TEST) += gup_test.o
+obj-$(CONFIG_DMAPOOL_TEST) += dmapool_test.o
obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o
obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o
obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o
diff --git a/mm/dmapool_test.c b/mm/dmapool_test.c
new file mode 100644
index 000000000000..370fb9e209ef
--- /dev/null
+++ b/mm/dmapool_test.c
@@ -0,0 +1,147 @@
+#include <linux/device.h>
+#include <linux/dma-map-ops.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/kernel.h>
+#include <linux/ktime.h>
+#include <linux/module.h>
+
+#define NR_TESTS (100)
+
+struct dma_pool_pair {
+ dma_addr_t dma;
+ void *v;
+};
+
+struct dmapool_parms {
+ size_t size;
+ size_t align;
+ size_t boundary;
+};
+
+static const struct dmapool_parms pool_parms[] = {
+ { .size = 16, .align = 16, .boundary = 0 },
+ { .size = 64, .align = 64, .boundary = 0 },
+ { .size = 256, .align = 256, .boundary = 0 },
+ { .size = 1024, .align = 1024, .boundary = 0 },
+ { .size = 4096, .align = 4096, .boundary = 0 },
+ { .size = 68, .align = 32, .boundary = 4096 },
+};
+
+static struct dma_pool *pool;
+static struct device test_dev;
+static u64 dma_mask;
+
+static inline int nr_blocks(int size)
+{
+ return clamp_t(int, (PAGE_SIZE / size) * 512, 1024, 8192);
+}
+
+static int dmapool_test_alloc(struct dma_pool_pair *p, int blocks)
+{
+ int i;
+
+ for (i = 0; i < blocks; i++) {
+ p[i].v = dma_pool_alloc(pool, GFP_KERNEL,
+ &p[i].dma);
+ if (!p[i].v)
+ goto pool_fail;
+ }
+
+ for (i = 0; i < blocks; i++)
+ dma_pool_free(pool, p[i].v, p[i].dma);
+
+ return 0;
+
+pool_fail:
+ for (--i; i >= 0; i--)
+ dma_pool_free(pool, p[i].v, p[i].dma);
+ return -ENOMEM;
+}
+
+static int dmapool_test_block(const struct dmapool_parms *parms)
+{
+ int blocks = nr_blocks(parms->size);
+ ktime_t start_time, end_time;
+ struct dma_pool_pair *p;
+ int i, ret;
+
+ p = kcalloc(blocks, sizeof(*p), GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+
+ pool = dma_pool_create("test pool", &test_dev, parms->size,
+ parms->align, parms->boundary);
+ if (!pool) {
+ ret = -ENOMEM;
+ goto free_pairs;
+ }
+
+ start_time = ktime_get();
+ for (i = 0; i < NR_TESTS; i++) {
+ ret = dmapool_test_alloc(p, blocks);
+ if (ret)
+ goto free_pool;
+ if (need_resched())
+ cond_resched();
+ }
+ end_time = ktime_get();
+
+ printk("dmapool test: size:%-4zu align:%-4zu blocks:%-4d time:%llu\n",
+ parms->size, parms->align, blocks,
+ ktime_us_delta(end_time, start_time));
+
+free_pool:
+ dma_pool_destroy(pool);
+free_pairs:
+ kfree(p);
+ return ret;
+}
+
+static void dmapool_test_release(struct device *dev)
+{
+}
+
+static int dmapool_checks(void)
+{
+ int i, ret;
+
+ ret = dev_set_name(&test_dev, "dmapool-test");
+ if (ret)
+ return ret;
+
+ ret = device_register(&test_dev);
+ if (ret) {
+ printk("%s: register failed:%d\n", __func__, ret);
+ goto put_device;
+ }
+
+ test_dev.release = dmapool_test_release;
+ set_dma_ops(&test_dev, NULL);
+ test_dev.dma_mask = &dma_mask;
+ ret = dma_set_mask_and_coherent(&test_dev, DMA_BIT_MASK(64));
+ if (ret) {
+ printk("%s: mask failed:%d\n", __func__, ret);
+ goto del_device;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(pool_parms); i++) {
+ ret = dmapool_test_block(&pool_parms[i]);
+ if (ret)
+ break;
+ }
+
+del_device:
+ device_del(&test_dev);
+put_device:
+ put_device(&test_dev);
+ return ret;
+}
+
+static void dmapool_exit(void)
+{
+}
+
+module_init(dmapool_checks);
+module_exit(dmapool_exit);
+MODULE_LICENSE("GPL");