Disable IOStatsContext/PerfContext if no thread local (#8117)

Summary:
Before this PR, `get_iostats_context()` will silently return a nullptr if no thread_local support is detected.
This can be the result of build_detect_platform's failure to compile the simple code snippet on certain platforms, as
reported in https://github.com/facebook/mysql-5.6/issues/904.
To be safe, we should fail the compilation if user does not opt out IOStatsContext and
ROCKSDB_SUPPORT_THREAD_LOCAL is not defined.

If RocksDB relies on c++11, can we just always use thread_local? It turns out there might be
performance concerns (https://github.com/facebook/rocksdb/issues/5774),
which is beyond the scope of this PR. We can revisit this later. Here, we stick to the original impl.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8117

Reviewed By: ajkr

Differential Revision: D27356847

Pulled By: riversand963

fbshipit-source-id: f7d5776842277598d8341b955febb601946801ae
main
Yanqin Jin 4 years ago committed by Facebook GitHub Bot
parent bb75092574
commit fd00f39f97
  1. 11
      CMakeLists.txt
  2. 1
      HISTORY.md
  3. 10
      include/rocksdb/iostats_context.h
  4. 11
      include/rocksdb/perf_context.h
  5. 20
      monitoring/iostats_context.cc
  6. 6
      monitoring/iostats_context_imp.h
  7. 22
      monitoring/perf_context.cc

@ -326,12 +326,23 @@ CHECK_CXX_SOURCE_COMPILES("
#endif
int main() {
static __thread int tls;
(void)tls;
}
" HAVE_THREAD_LOCAL)
if(HAVE_THREAD_LOCAL)
add_definitions(-DROCKSDB_SUPPORT_THREAD_LOCAL)
endif()
option(WITH_IOSTATS_CONTEXT "Enable IO stats context" ON)
if (NOT WITH_IOSTATS_CONTEXT)
add_definitions(-DNIOSTATS_CONTEXT)
endif()
option(WITH_PERF_CONTEXT "Enable perf context" ON)
if (NOT WITH_PERF_CONTEXT)
add_definitions(-DNPERF_CONTEXT)
endif()
option(FAIL_ON_WARNINGS "Treat compile warnings as errors" ON)
if(FAIL_ON_WARNINGS)
if(MSVC)

@ -4,6 +4,7 @@
* `ColumnFamilyOptions::sample_for_compression` now takes effect for creation of all block-based tables. Previously it only took effect for block-based tables created by flush.
* `CompactFiles()` can no longer compact files from lower level to up level, which has the risk to corrupt DB (details: #8063). The validation is also added to all compactions.
* Fixed some cases in which DB::OpenForReadOnly() could write to the filesystem. If you want a Logger with a read-only DB, you must now set DBOptions::info_log yourself, such as using CreateLoggerFromOptions().
* get_iostats_context() will never return nullptr. If thread-local support is not available, and user does not opt-out iostats context, then compilation will fail. The same applies to perf context as well.
### Bug Fixes
* Use thread-safe `strerror_r()` to get error messages.

@ -50,7 +50,15 @@ struct IOStatsContext {
uint64_t cpu_read_nanos;
};
// Get Thread-local IOStatsContext object pointer
// If RocksDB is compiled with -DNIOSTATS_CONTEXT, then a pointer to a global,
// non-thread-local IOStatsContext object will be returned. Attempts to update
// this object will be ignored, and reading from it will also be no-op.
// Otherwise,
// a) if thread-local is supported on the platform, then a pointer to
// a thread-local IOStatsContext object will be returned.
// b) if thread-local is NOT supported, then compilation will fail.
//
// This function never returns nullptr.
IOStatsContext* get_iostats_context();
} // namespace ROCKSDB_NAMESPACE

@ -230,8 +230,15 @@ struct PerfContext {
bool per_level_perf_context_enabled = false;
};
// Get Thread-local PerfContext object pointer
// if defined(NPERF_CONTEXT), then the pointer is not thread-local
// If RocksDB is compiled with -DNPERF_CONTEXT, then a pointer to a global,
// non-thread-local PerfContext object will be returned. Attempts to update
// this object will be ignored, and reading from it will also be no-op.
// Otherwise,
// a) if thread-local is supported on the platform, then a pointer to
// a thread-local PerfContext object will be returned.
// b) if thread-local is NOT supported, then compilation will fail.
//
// This function never returns nullptr.
PerfContext* get_perf_context();
} // namespace ROCKSDB_NAMESPACE

@ -9,19 +9,23 @@
namespace ROCKSDB_NAMESPACE {
#ifdef ROCKSDB_SUPPORT_THREAD_LOCAL
#ifdef NIOSTATS_CONTEXT
// Should not be used because the counters are not thread-safe.
// Put here just to make get_iostats_context() simple without ifdef.
static IOStatsContext iostats_context;
#elif defined(ROCKSDB_SUPPORT_THREAD_LOCAL)
__thread IOStatsContext iostats_context;
#else
#error \
"No thread-local support. Disable iostats context with -DNIOSTATS_CONTEXT."
#endif
IOStatsContext* get_iostats_context() {
#ifdef ROCKSDB_SUPPORT_THREAD_LOCAL
return &iostats_context;
#else
return nullptr;
#endif
}
void IOStatsContext::Reset() {
#ifndef NIOSTATS_CONTEXT
thread_pool_id = Env::Priority::TOTAL;
bytes_read = 0;
bytes_written = 0;
@ -35,6 +39,7 @@ void IOStatsContext::Reset() {
logger_nanos = 0;
cpu_write_nanos = 0;
cpu_read_nanos = 0;
#endif //! NIOSTATS_CONTEXT
}
#define IOSTATS_CONTEXT_OUTPUT(counter) \
@ -43,6 +48,10 @@ void IOStatsContext::Reset() {
}
std::string IOStatsContext::ToString(bool exclude_zero_counters) const {
#ifdef NIOSTATS_CONTEXT
(void)exclude_zero_counters;
return "";
#else
std::ostringstream ss;
IOSTATS_CONTEXT_OUTPUT(thread_pool_id);
IOSTATS_CONTEXT_OUTPUT(bytes_read);
@ -61,6 +70,7 @@ std::string IOStatsContext::ToString(bool exclude_zero_counters) const {
std::string str = ss.str();
str.erase(str.find_last_not_of(", ") + 1);
return str;
#endif //! NIOSTATS_CONTEXT
}
} // namespace ROCKSDB_NAMESPACE

@ -7,7 +7,7 @@
#include "monitoring/perf_step_timer.h"
#include "rocksdb/iostats_context.h"
#ifdef ROCKSDB_SUPPORT_THREAD_LOCAL
#if defined(ROCKSDB_SUPPORT_THREAD_LOCAL) && !defined(NIOSTATS_CONTEXT)
namespace ROCKSDB_NAMESPACE {
extern __thread IOStatsContext iostats_context;
} // namespace ROCKSDB_NAMESPACE
@ -44,7 +44,7 @@ extern __thread IOStatsContext iostats_context;
PerfLevel::kEnableTimeAndCPUTimeExceptForMutex); \
iostats_step_timer_##metric.Start();
#else // ROCKSDB_SUPPORT_THREAD_LOCAL
#else // ROCKSDB_SUPPORT_THREAD_LOCAL && !NIOSTATS_CONTEXT
#define IOSTATS_ADD(metric, value)
#define IOSTATS_ADD_IF_POSITIVE(metric, value)
@ -57,4 +57,4 @@ extern __thread IOStatsContext iostats_context;
#define IOSTATS_TIMER_GUARD(metric)
#define IOSTATS_CPU_TIMER_GUARD(metric, clock) static_cast<void>(clock)
#endif // ROCKSDB_SUPPORT_THREAD_LOCAL
#endif // ROCKSDB_SUPPORT_THREAD_LOCAL && !NIOSTATS_CONTEXT

@ -9,26 +9,22 @@
namespace ROCKSDB_NAMESPACE {
#if defined(NPERF_CONTEXT) || !defined(ROCKSDB_SUPPORT_THREAD_LOCAL)
#if defined(NPERF_CONTEXT)
// Should not be used because the counters are not thread-safe.
// Put here just to make get_perf_context() simple without ifdef.
PerfContext perf_context;
#else
#elif defined(ROCKSDB_SUPPORT_THREAD_LOCAL)
#if defined(OS_SOLARIS)
__thread PerfContext perf_context_;
#else
__thread PerfContext perf_context;
#else // OS_SOLARIS
thread_local PerfContext perf_context;
#endif
#endif // OS_SOLARIS
#else
#error "No thread-local support. Disable perf context with -DNPERF_CONTEXT."
#endif
PerfContext* get_perf_context() {
#if defined(NPERF_CONTEXT) || !defined(ROCKSDB_SUPPORT_THREAD_LOCAL)
return &perf_context;
#else
#if defined(OS_SOLARIS)
return &perf_context_;
#else
return &perf_context;
#endif
#endif
}
PerfContext::~PerfContext() {

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