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// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <sched.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
#include "gtest/gtest.h"
#include "absl/strings/str_split.h"
#include "test/util/cleanup.h"
#include "test/util/fs_util.h"
#include "test/util/posix_error.h"
#include "test/util/test_util.h"
#include "test/util/thread_util.h"
namespace gvisor {
namespace testing {
namespace {
// These tests are for both the sched_getaffinity(2) and sched_setaffinity(2)
// syscalls.
class AffinityTest : public ::testing::Test {
protected:
void SetUp() override {
EXPECT_THAT(
// Needs use the raw syscall to get the actual size.
cpuset_size_ = syscall(SYS_sched_getaffinity, /*pid=*/0,
sizeof(cpu_set_t), &mask_),
SyscallSucceeds());
// Lots of tests rely on having more than 1 logical processor available.
EXPECT_GT(CPU_COUNT(&mask_), 1);
}
static PosixError ClearLowestBit(cpu_set_t* mask, size_t cpus) {
const size_t mask_size = CPU_ALLOC_SIZE(cpus);
for (size_t n = 0; n < cpus; ++n) {
if (CPU_ISSET_S(n, mask_size, mask)) {
CPU_CLR_S(n, mask_size, mask);
return NoError();
}
}
return PosixError(EINVAL, "No bit to clear, mask is empty");
}
PosixError ClearLowestBit() { return ClearLowestBit(&mask_, CPU_SETSIZE); }
// Stores the initial cpu mask for this process.
cpu_set_t mask_ = {};
int cpuset_size_ = 0;
};
// sched_getaffinity(2) is implemented.
TEST_F(AffinityTest, SchedGetAffinityImplemented) {
EXPECT_THAT(sched_getaffinity(/*pid=*/0, sizeof(cpu_set_t), &mask_),
SyscallSucceeds());
}
// PID is not found.
TEST_F(AffinityTest, SchedGetAffinityInvalidPID) {
// Flaky, but it's tough to avoid a race condition when finding an unused pid
EXPECT_THAT(sched_getaffinity(/*pid=*/INT_MAX - 1, sizeof(cpu_set_t), &mask_),
SyscallFailsWithErrno(ESRCH));
}
// PID is not found.
TEST_F(AffinityTest, SchedSetAffinityInvalidPID) {
// Flaky, but it's tough to avoid a race condition when finding an unused pid
EXPECT_THAT(sched_setaffinity(/*pid=*/INT_MAX - 1, sizeof(cpu_set_t), &mask_),
SyscallFailsWithErrno(ESRCH));
}
TEST_F(AffinityTest, SchedSetAffinityZeroMask) {
CPU_ZERO(&mask_);
EXPECT_THAT(sched_setaffinity(/*pid=*/0, sizeof(cpu_set_t), &mask_),
SyscallFailsWithErrno(EINVAL));
}
// N.B. This test case relies on cpuset_size_ larger than the actual number of
// of all existing CPUs. Check your machine if the test fails.
TEST_F(AffinityTest, SchedSetAffinityNonexistentCPUDropped) {
cpu_set_t mask = mask_;
// Add a nonexistent CPU.
//
// The number needs to be larger than the possible number of CPU available,
// but smaller than the number of the CPU that the kernel claims to support --
// it's implicitly returned by raw sched_getaffinity syscall.
CPU_SET(cpuset_size_ * 8 - 1, &mask);
EXPECT_THAT(
// Use raw syscall because it will be rejected by the libc wrapper
// otherwise.
syscall(SYS_sched_setaffinity, /*pid=*/0, sizeof(cpu_set_t), &mask),
SyscallSucceeds())
<< "failed with cpumask : " << CPUSetToString(mask)
<< ", cpuset_size_ : " << cpuset_size_;
cpu_set_t newmask;
EXPECT_THAT(sched_getaffinity(/*pid=*/0, sizeof(cpu_set_t), &newmask),
SyscallSucceeds());
EXPECT_TRUE(CPU_EQUAL(&mask_, &newmask))
<< "got: " << CPUSetToString(newmask)
<< " != expected: " << CPUSetToString(mask_);
}
TEST_F(AffinityTest, SchedSetAffinityOnlyNonexistentCPUFails) {
// Make an empty cpu set.
CPU_ZERO(&mask_);
// Add a nonexistent CPU.
//
// The number needs to be larger than the possible number of CPU available,
// but smaller than the number of the CPU that the kernel claims to support --
// it's implicitly returned by raw sched_getaffinity syscall.
int cpu = cpuset_size_ * 8 - 1;
if (cpu <= NumCPUs()) {
GTEST_SKIP() << "Skipping test: cpu " << cpu << " exists";
}
CPU_SET(cpu, &mask_);
EXPECT_THAT(
// Use raw syscall because it will be rejected by the libc wrapper
// otherwise.
syscall(SYS_sched_setaffinity, /*pid=*/0, sizeof(cpu_set_t), &mask_),
SyscallFailsWithErrno(EINVAL));
}
TEST_F(AffinityTest, SchedSetAffinityInvalidSize) {
EXPECT_GT(cpuset_size_, 0);
// Not big enough.
EXPECT_THAT(sched_getaffinity(/*pid=*/0, cpuset_size_ - 1, &mask_),
SyscallFailsWithErrno(EINVAL));
// Not a multiple of word size.
EXPECT_THAT(sched_getaffinity(/*pid=*/0, cpuset_size_ + 1, &mask_),
SyscallFailsWithErrno(EINVAL));
}
TEST_F(AffinityTest, Sanity) {
ASSERT_NO_ERRNO(ClearLowestBit());
EXPECT_THAT(sched_setaffinity(/*pid=*/0, sizeof(cpu_set_t), &mask_),
SyscallSucceeds());
cpu_set_t newmask;
EXPECT_THAT(sched_getaffinity(/*pid=*/0, sizeof(cpu_set_t), &newmask),
SyscallSucceeds());
EXPECT_TRUE(CPU_EQUAL(&mask_, &newmask))
<< "got: " << CPUSetToString(newmask)
<< " != expected: " << CPUSetToString(mask_);
}
TEST_F(AffinityTest, NewThread) {
SKIP_IF(CPU_COUNT(&mask_) < 3);
ASSERT_NO_ERRNO(ClearLowestBit());
ASSERT_NO_ERRNO(ClearLowestBit());
EXPECT_THAT(sched_setaffinity(/*pid=*/0, sizeof(cpu_set_t), &mask_),
SyscallSucceeds());
ScopedThread([this]() {
cpu_set_t child_mask;
ASSERT_THAT(sched_getaffinity(/*pid=*/0, sizeof(cpu_set_t), &child_mask),
SyscallSucceeds());
ASSERT_TRUE(CPU_EQUAL(&child_mask, &mask_))
<< "child cpu mask: " << CPUSetToString(child_mask)
<< " != parent cpu mask: " << CPUSetToString(mask_);
});
}
TEST_F(AffinityTest, ConsistentWithProcCpuInfo) {
// Count how many cpus are shown in /proc/cpuinfo.
std::string cpuinfo = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/cpuinfo"));
int count = 0;
for (auto const& line : absl::StrSplit(cpuinfo, '\n')) {
if (absl::StartsWith(line, "processor")) {
count++;
}
}
EXPECT_GE(count, CPU_COUNT(&mask_));
}
TEST_F(AffinityTest, ConsistentWithProcStat) {
// Count how many cpus are shown in /proc/stat.
std::string stat = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/stat"));
int count = 0;
for (auto const& line : absl::StrSplit(stat, '\n')) {
if (absl::StartsWith(line, "cpu") && !absl::StartsWith(line, "cpu ")) {
count++;
}
}
EXPECT_GE(count, CPU_COUNT(&mask_));
}
TEST_F(AffinityTest, SmallCpuMask) {
const int num_cpus = NumCPUs();
const size_t mask_size = CPU_ALLOC_SIZE(num_cpus);
cpu_set_t* mask = CPU_ALLOC(num_cpus);
ASSERT_NE(mask, nullptr);
const auto free_mask = Cleanup([&] { CPU_FREE(mask); });
CPU_ZERO_S(mask_size, mask);
ASSERT_THAT(sched_getaffinity(0, mask_size, mask), SyscallSucceeds());
}
TEST_F(AffinityTest, LargeCpuMask) {
// Allocate mask bigger than cpu_set_t normally allocates.
const size_t cpus = CPU_SETSIZE * 8;
const size_t mask_size = CPU_ALLOC_SIZE(cpus);
cpu_set_t* large_mask = CPU_ALLOC(cpus);
auto free_mask = Cleanup([large_mask] { CPU_FREE(large_mask); });
CPU_ZERO_S(mask_size, large_mask);
// Check that get affinity with large mask works as expected.
ASSERT_THAT(sched_getaffinity(/*pid=*/0, mask_size, large_mask),
SyscallSucceeds());
EXPECT_TRUE(CPU_EQUAL(&mask_, large_mask))
<< "got: " << CPUSetToString(*large_mask, cpus)
<< " != expected: " << CPUSetToString(mask_);
// Check that set affinity with large mask works as expected.
ASSERT_NO_ERRNO(ClearLowestBit(large_mask, cpus));
EXPECT_THAT(sched_setaffinity(/*pid=*/0, mask_size, large_mask),
SyscallSucceeds());
cpu_set_t* new_mask = CPU_ALLOC(cpus);
auto free_new_mask = Cleanup([new_mask] { CPU_FREE(new_mask); });
CPU_ZERO_S(mask_size, new_mask);
EXPECT_THAT(sched_getaffinity(/*pid=*/0, mask_size, new_mask),
SyscallSucceeds());
EXPECT_TRUE(CPU_EQUAL_S(mask_size, large_mask, new_mask))
<< "got: " << CPUSetToString(*new_mask, cpus)
<< " != expected: " << CPUSetToString(*large_mask, cpus);
}
} // namespace
} // namespace testing
} // namespace gvisor
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