From: Benjamin Barenblat <bbaren@google.com>
Subject: Ignore missing CPU frequency on more architectures
Forwarded: yes
Applied-Upstream: https://github.com/abseil/abseil-cpp/commit/1918ad2ae38aa32c74b558b322479a8efdd76363

Linux on MIPS, PA-RISC, RISC-V, and SystemZ doesn’t expose the nominal CPU
frequency via /sys, so don’t worry if `NominalCPUFrequency` returns 1.0 on those
platforms.

Some POWER machines expose the CPU frequency; others do not. Since we can’t
predict which type of machine the tests will run on, simply disable testing for
`NominalCPUFrequency` on POWER.

The author works at Google. Upstream applied this patch as Piper revision
347079873 and exported it to GitHub; the Applied-Upstream URL above points to
the exported commit.

--- a/absl/base/internal/sysinfo_test.cc
+++ b/absl/base/internal/sysinfo_test.cc
@@ -37,17 +37,28 @@ TEST(SysinfoTest, NumCPUs) {
       << "NumCPUs() should not have the default value of 0";
 }
 
+// Ensure that NominalCPUFrequency returns a reasonable value, or 1.00 on
+// platforms where the CPU frequency is not available through sysfs.
+//
+// POWER is particularly problematic here; some Linux kernels expose the CPU
+// frequency, while others do not. Since we can't predict a priori what a given
+// machine is going to do, just disable this test on POWER on Linux.
+#if !(defined(__linux) && (defined(__ppc64__) || defined(__PPC64__)))
 TEST(SysinfoTest, NominalCPUFrequency) {
-#if !(defined(__aarch64__) && defined(__linux__)) && !defined(__EMSCRIPTEN__)
-  EXPECT_GE(NominalCPUFrequency(), 1000.0)
-      << "NominalCPUFrequency() did not return a reasonable value";
-#else
-  // Aarch64 cannot read the CPU frequency from sysfs, so we get back 1.0.
-  // Emscripten does not have a sysfs to read from at all.
+  // Linux only exposes the CPU frequency on certain architectures, and
+  // Emscripten doesn't expose it at all.
+#if defined(__linux__) &&                                                  \
+        (defined(__aarch64__) || defined(__hppa__) || defined(__mips__) || \
+         defined(__riscv) || defined(__s390x__)) ||                        \
+    defined(__EMSCRIPTEN__)
   EXPECT_EQ(NominalCPUFrequency(), 1.0)
       << "CPU frequency detection was fixed! Please update unittest.";
+#else
+  EXPECT_GE(NominalCPUFrequency(), 1000.0)
+      << "NominalCPUFrequency() did not return a reasonable value";
 #endif
 }
+#endif
 
 TEST(SysinfoTest, GetTID) {
   EXPECT_EQ(GetTID(), GetTID());  // Basic compile and equality test.