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Commit 1c47bb50 authored by Mitchel Humpherys's avatar Mitchel Humpherys Committed by Patrick Daly
Browse files

iommu/iommu-debug: Use more iterations while profiling 



Currently we only take one sample per buffer size per API when doing
profiling.  This results in high run-to-run variance in the results.
Use more iterations to help smooth this out.

Change-Id: I3779007a2f69ef79b573285b2422554f42dda99f
Signed-off-by: default avatarMitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: default avatarPatrick Daly <pdaly@codeaurora.org>
parent 020f90f2

drivers/iommu/iommu-debug.c

+60 −41
Original line number Diff line number Diff line
@@ -455,6 +455,8 @@ static const char * const _size_to_string(unsigned long size) 
	return "unknown size, please add to _size_to_string";

}



#define ITERS_PER_OP 100



static void iommu_debug_device_profiling(struct seq_file *s, struct device *dev,

					 bool secure)

{
@@ -496,13 +498,16 @@ static void iommu_debug_device_profiling(struct seq_file *s, struct device *dev, 
		goto out_domain_free;

	}



	seq_printf(s, "(average over %d iterations)\n", ITERS_PER_OP);

	seq_printf(s, "%8s %15s %12s\n", "size", "iommu_map", "iommu_unmap");

	for (sz = sizes; *sz; ++sz) {

		unsigned long size = *sz;

		size_t unmapped;

		s64 map_elapsed_us, unmap_elapsed_us;

		u64 map_elapsed_us = 0, unmap_elapsed_us = 0;

		struct timespec tbefore, tafter, diff;

		int i;



		for (i = 0; i < ITERS_PER_OP; ++i) {

			getnstimeofday(&tbefore);

			if (iommu_map(domain, iova, paddr, size,

				      IOMMU_READ | IOMMU_WRITE)) {
@@ -511,18 +516,24 @@ static void iommu_debug_device_profiling(struct seq_file *s, struct device *dev, 
			}

			getnstimeofday(&tafter);

			diff = timespec_sub(tafter, tbefore);

		map_elapsed_us = div_s64(timespec_to_ns(&diff), 1000);

			map_elapsed_us += div_s64(timespec_to_ns(&diff), 1000);



			getnstimeofday(&tbefore);

			unmapped = iommu_unmap(domain, iova, size);

			if (unmapped != size) {

			seq_printf(s, "Only unmapped %zx instead of %zx\n",

				seq_printf(s,

					   "Only unmapped %zx instead of %zx\n",

					   unmapped, size);

				continue;

			}

			getnstimeofday(&tafter);

			diff = timespec_sub(tafter, tbefore);

		unmap_elapsed_us = div_s64(timespec_to_ns(&diff), 1000);

			unmap_elapsed_us += div_s64(timespec_to_ns(&diff),

						    1000);

		}



		map_elapsed_us /= ITERS_PER_OP;

		unmap_elapsed_us /= ITERS_PER_OP;



		seq_printf(s, "%8s %12lld us %9lld us\n", _size_to_string(size),

			map_elapsed_us, unmap_elapsed_us);
@@ -533,10 +544,11 @@ static void iommu_debug_device_profiling(struct seq_file *s, struct device *dev, 
	for (sz = sizes; *sz; ++sz) {

		unsigned long size = *sz;

		size_t unmapped;

		s64 map_elapsed_us, unmap_elapsed_us;

		u64 map_elapsed_us = 0, unmap_elapsed_us = 0;

		struct timespec tbefore, tafter, diff;

		struct sg_table table;

		unsigned long chunk_size = SZ_4K;

		int i;



		if (iommu_debug_build_phoney_sg_table(dev, &table, size,

						      chunk_size)) {
@@ -545,6 +557,7 @@ static void iommu_debug_device_profiling(struct seq_file *s, struct device *dev, 
			goto out_detach;

		}



		for (i = 0; i < ITERS_PER_OP; ++i) {

			getnstimeofday(&tbefore);

			if (iommu_map_sg(domain, iova, table.sgl, table.nents,

					 IOMMU_READ | IOMMU_WRITE) != size) {
@@ -553,18 +566,24 @@ static void iommu_debug_device_profiling(struct seq_file *s, struct device *dev, 
			}

			getnstimeofday(&tafter);

			diff = timespec_sub(tafter, tbefore);

		map_elapsed_us = div_s64(timespec_to_ns(&diff), 1000);

			map_elapsed_us += div_s64(timespec_to_ns(&diff), 1000);



			getnstimeofday(&tbefore);

			unmapped = iommu_unmap(domain, iova, size);

			if (unmapped != size) {

			seq_printf(s, "Only unmapped %zx instead of %zx\n",

				seq_printf(s,

					   "Only unmapped %zx instead of %zx\n",

					   unmapped, size);

				goto next;

			}

			getnstimeofday(&tafter);

			diff = timespec_sub(tafter, tbefore);

		unmap_elapsed_us = div_s64(timespec_to_ns(&diff), 1000);

			unmap_elapsed_us += div_s64(timespec_to_ns(&diff),

						    1000);

		}



		map_elapsed_us /= ITERS_PER_OP;

		unmap_elapsed_us /= ITERS_PER_OP;



		seq_printf(s, "%8s %12lld us %9lld us\n", _size_to_string(size),

			map_elapsed_us, unmap_elapsed_us);