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authorJohannes Berg <johannes.berg@intel.com>2022-10-10 11:03:31 +0200
committerJohannes Berg <johannes.berg@intel.com>2022-10-10 11:03:43 +0200
commitdfd2d876b3fda1790bc0239ba4c6967e25d16e91 (patch)
tree45c2ec4b25afdf7b521dec642f6b75112bb401a3 /tools/testing/selftests/kvm/access_tracking_perf_test.c
parenta790cc3a4fad75048295571a350b95b87e022a5a (diff)
parent10d5ea5a436da8d60cdb5845f454d595accdbce0 (diff)
downloadlinux-dfd2d876b3fda1790bc0239ba4c6967e25d16e91.tar.bz2
Merge remote-tracking branch 'wireless/main' into wireless-next
Pull in wireless/main content since some new code would otherwise conflict with it. Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'tools/testing/selftests/kvm/access_tracking_perf_test.c')
-rw-r--r--tools/testing/selftests/kvm/access_tracking_perf_test.c25
1 files changed, 16 insertions, 9 deletions
diff --git a/tools/testing/selftests/kvm/access_tracking_perf_test.c b/tools/testing/selftests/kvm/access_tracking_perf_test.c
index 1c2749b1481a..76c583a07ea2 100644
--- a/tools/testing/selftests/kvm/access_tracking_perf_test.c
+++ b/tools/testing/selftests/kvm/access_tracking_perf_test.c
@@ -31,8 +31,9 @@
* These limitations are worked around in this test by using a large enough
* region of memory for each vCPU such that the number of translations cached in
* the TLB and the number of pages held in pagevecs are a small fraction of the
- * overall workload. And if either of those conditions are not true this test
- * will fail rather than silently passing.
+ * overall workload. And if either of those conditions are not true (for example
+ * in nesting, where TLB size is unlimited) this test will print a warning
+ * rather than silently passing.
*/
#include <inttypes.h>
#include <limits.h>
@@ -172,17 +173,23 @@ static void mark_vcpu_memory_idle(struct kvm_vm *vm,
vcpu_idx, no_pfn, pages);
/*
- * Test that at least 90% of memory has been marked idle (the rest might
- * not be marked idle because the pages have not yet made it to an LRU
- * list or the translations are still cached in the TLB). 90% is
+ * Check that at least 90% of memory has been marked idle (the rest
+ * might not be marked idle because the pages have not yet made it to an
+ * LRU list or the translations are still cached in the TLB). 90% is
* arbitrary; high enough that we ensure most memory access went through
* access tracking but low enough as to not make the test too brittle
* over time and across architectures.
+ *
+ * Note that when run in nested virtualization, this check will trigger
+ * much more frequently because TLB size is unlimited and since no flush
+ * happens, much more pages are cached there and guest won't see the
+ * "idle" bit cleared.
*/
- TEST_ASSERT(still_idle < pages / 10,
- "vCPU%d: Too many pages still idle (%"PRIu64 " out of %"
- PRIu64 ").\n",
- vcpu_idx, still_idle, pages);
+ if (still_idle < pages / 10)
+ printf("WARNING: vCPU%d: Too many pages still idle (%" PRIu64
+ "out of %" PRIu64 "), this will affect performance results"
+ ".\n",
+ vcpu_idx, still_idle, pages);
close(page_idle_fd);
close(pagemap_fd);