Revert "Revert "Restrict the number of threads in C++ sync server""

pull/16215/head
Sree Kuchibhotla 6 years ago committed by GitHub
parent 92fd2620ab
commit bdd13cb0ae
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
  1. 1
      grpc.def
  2. 4
      include/grpc/grpc.h
  3. 16
      include/grpcpp/resource_quota.h
  4. 3
      include/grpcpp/server.h
  5. 78
      src/core/lib/iomgr/resource_quota.cc
  6. 16
      src/core/lib/iomgr/resource_quota.h
  7. 4
      src/cpp/common/resource_quota_cc.cc
  8. 2
      src/cpp/server/server_builder.cc
  9. 31
      src/cpp/server/server_cc.cc
  10. 53
      src/cpp/thread_manager/thread_manager.cc
  11. 48
      src/cpp/thread_manager/thread_manager.h
  12. 2
      src/ruby/ext/grpc/rb_grpc_imports.generated.c
  13. 3
      src/ruby/ext/grpc/rb_grpc_imports.generated.h
  14. 97
      test/core/iomgr/resource_quota_test.cc
  15. 1
      test/core/surface/public_headers_must_be_c89.c
  16. 149
      test/cpp/thread_manager/thread_manager_test.cc

@ -68,6 +68,7 @@ EXPORTS
grpc_resource_quota_ref
grpc_resource_quota_unref
grpc_resource_quota_resize
grpc_resource_quota_set_max_threads
grpc_resource_quota_arg_vtable
grpc_channelz_get_top_channels
grpc_channelz_get_channel

@ -450,6 +450,10 @@ GRPCAPI void grpc_resource_quota_unref(grpc_resource_quota* resource_quota);
GRPCAPI void grpc_resource_quota_resize(grpc_resource_quota* resource_quota,
size_t new_size);
/** Update the size of the maximum number of threads allowed */
GRPCAPI void grpc_resource_quota_set_max_threads(
grpc_resource_quota* resource_quota, int new_max_threads);
/** Fetch a vtable for a grpc_channel_arg that points to a grpc_resource_quota
*/
GRPCAPI const grpc_arg_pointer_vtable* grpc_resource_quota_arg_vtable(void);

@ -26,10 +26,10 @@ struct grpc_resource_quota;
namespace grpc {
/// ResourceQuota represents a bound on memory usage by the gRPC library.
/// A ResourceQuota can be attached to a server (via \a ServerBuilder),
/// ResourceQuota represents a bound on memory and thread usage by the gRPC
/// library. A ResourceQuota can be attached to a server (via \a ServerBuilder),
/// or a client channel (via \a ChannelArguments).
/// gRPC will attempt to keep memory used by all attached entities
/// gRPC will attempt to keep memory and threads used by all attached entities
/// below the ResourceQuota bound.
class ResourceQuota final : private GrpcLibraryCodegen {
public:
@ -44,6 +44,16 @@ class ResourceQuota final : private GrpcLibraryCodegen {
/// No time bound is given for this to occur however.
ResourceQuota& Resize(size_t new_size);
/// Set the max number of threads that can be allocated from this
/// ResourceQuota object.
///
/// If the new_max_threads value is smaller than the current value, no new
/// threads are allocated until the number of active threads fall below
/// new_max_threads. There is no time bound on when this may happen i.e none
/// of the current threads are forcefully destroyed and all threads run their
/// normal course.
ResourceQuota& SetMaxThreads(int new_max_threads);
grpc_resource_quota* c_resource_quota() const { return impl_; }
private:

@ -144,7 +144,8 @@ class Server : public ServerInterface, private GrpcLibraryCodegen {
Server(int max_message_size, ChannelArguments* args,
std::shared_ptr<std::vector<std::unique_ptr<ServerCompletionQueue>>>
sync_server_cqs,
int min_pollers, int max_pollers, int sync_cq_timeout_msec);
grpc_resource_quota* server_rq, int min_pollers, int max_pollers,
int sync_cq_timeout_msec);
/// Start the server.
///

@ -96,6 +96,9 @@ struct grpc_resource_user {
list, false otherwise */
bool added_to_free_pool;
/* The number of threads currently allocated to this resource user */
gpr_atm num_threads_allocated;
/* Reclaimers: index 0 is the benign reclaimer, 1 is the destructive reclaimer
*/
grpc_closure* reclaimers[2];
@ -135,12 +138,33 @@ struct grpc_resource_quota {
gpr_atm last_size;
/* Mutex to protect max_threads and num_threads_allocated */
/* Note: We could have used gpr_atm for max_threads and num_threads_allocated
* and avoid having this mutex; but in that case, each invocation of the
* function grpc_resource_user_allocate_threads() would have had to do at
* least two atomic loads (for max_threads and num_threads_allocated) followed
* by a CAS (on num_threads_allocated).
* Moreover, we expect grpc_resource_user_allocate_threads() to be often
* called concurrently thereby increasing the chances of failing the CAS
* operation. This additional complexity is not worth the tiny perf gain we
* may (or may not) have by using atomics */
gpr_mu thread_count_mu;
/* Max number of threads allowed */
int max_threads;
/* Number of threads currently allocated via this resource_quota object */
int num_threads_allocated;
/* Has rq_step been scheduled to occur? */
bool step_scheduled;
/* Are we currently reclaiming memory */
bool reclaiming;
/* Closure around rq_step */
grpc_closure rq_step_closure;
/* Closure around rq_reclamation_done */
grpc_closure rq_reclamation_done_closure;
@ -524,6 +548,11 @@ static void ru_shutdown(void* ru, grpc_error* error) {
static void ru_destroy(void* ru, grpc_error* error) {
grpc_resource_user* resource_user = static_cast<grpc_resource_user*>(ru);
GPR_ASSERT(gpr_atm_no_barrier_load(&resource_user->refs) == 0);
// Free all the remaining thread quota
grpc_resource_user_free_threads(resource_user,
static_cast<int>(gpr_atm_no_barrier_load(
&resource_user->num_threads_allocated)));
for (int i = 0; i < GRPC_RULIST_COUNT; i++) {
rulist_remove(resource_user, static_cast<grpc_rulist>(i));
}
@ -594,6 +623,9 @@ grpc_resource_quota* grpc_resource_quota_create(const char* name) {
resource_quota->free_pool = INT64_MAX;
resource_quota->size = INT64_MAX;
gpr_atm_no_barrier_store(&resource_quota->last_size, GPR_ATM_MAX);
gpr_mu_init(&resource_quota->thread_count_mu);
resource_quota->max_threads = INT_MAX;
resource_quota->num_threads_allocated = 0;
resource_quota->step_scheduled = false;
resource_quota->reclaiming = false;
gpr_atm_no_barrier_store(&resource_quota->memory_usage_estimation, 0);
@ -616,6 +648,8 @@ grpc_resource_quota* grpc_resource_quota_create(const char* name) {
void grpc_resource_quota_unref_internal(grpc_resource_quota* resource_quota) {
if (gpr_unref(&resource_quota->refs)) {
// No outstanding thread quota
GPR_ASSERT(resource_quota->num_threads_allocated == 0);
GRPC_COMBINER_UNREF(resource_quota->combiner, "resource_quota");
gpr_free(resource_quota->name);
gpr_free(resource_quota);
@ -646,6 +680,15 @@ double grpc_resource_quota_get_memory_pressure(
(static_cast<double>(MEMORY_USAGE_ESTIMATION_MAX));
}
/* Public API */
void grpc_resource_quota_set_max_threads(grpc_resource_quota* resource_quota,
int new_max_threads) {
GPR_ASSERT(new_max_threads >= 0);
gpr_mu_lock(&resource_quota->thread_count_mu);
resource_quota->max_threads = new_max_threads;
gpr_mu_unlock(&resource_quota->thread_count_mu);
}
/* Public API */
void grpc_resource_quota_resize(grpc_resource_quota* resource_quota,
size_t size) {
@ -731,6 +774,7 @@ grpc_resource_user* grpc_resource_user_create(
grpc_closure_list_init(&resource_user->on_allocated);
resource_user->allocating = false;
resource_user->added_to_free_pool = false;
gpr_atm_no_barrier_store(&resource_user->num_threads_allocated, 0);
resource_user->reclaimers[0] = nullptr;
resource_user->reclaimers[1] = nullptr;
resource_user->new_reclaimers[0] = nullptr;
@ -785,6 +829,40 @@ void grpc_resource_user_shutdown(grpc_resource_user* resource_user) {
}
}
bool grpc_resource_user_allocate_threads(grpc_resource_user* resource_user,
int thread_count) {
GPR_ASSERT(thread_count >= 0);
bool is_success = false;
gpr_mu_lock(&resource_user->resource_quota->thread_count_mu);
grpc_resource_quota* rq = resource_user->resource_quota;
if (rq->num_threads_allocated + thread_count <= rq->max_threads) {
rq->num_threads_allocated += thread_count;
gpr_atm_no_barrier_fetch_add(&resource_user->num_threads_allocated,
thread_count);
is_success = true;
}
gpr_mu_unlock(&resource_user->resource_quota->thread_count_mu);
return is_success;
}
void grpc_resource_user_free_threads(grpc_resource_user* resource_user,
int thread_count) {
GPR_ASSERT(thread_count >= 0);
gpr_mu_lock(&resource_user->resource_quota->thread_count_mu);
grpc_resource_quota* rq = resource_user->resource_quota;
rq->num_threads_allocated -= thread_count;
int old_count = static_cast<int>(gpr_atm_no_barrier_fetch_add(
&resource_user->num_threads_allocated, -thread_count));
if (old_count < thread_count || rq->num_threads_allocated < 0) {
gpr_log(GPR_ERROR,
"Releasing more threads (%d) than currently allocated (rq threads: "
"%d, ru threads: %d)",
thread_count, rq->num_threads_allocated + thread_count, old_count);
abort();
}
gpr_mu_unlock(&resource_user->resource_quota->thread_count_mu);
}
void grpc_resource_user_alloc(grpc_resource_user* resource_user, size_t size,
grpc_closure* optional_on_done) {
gpr_mu_lock(&resource_user->mu);

@ -93,6 +93,22 @@ void grpc_resource_user_ref(grpc_resource_user* resource_user);
void grpc_resource_user_unref(grpc_resource_user* resource_user);
void grpc_resource_user_shutdown(grpc_resource_user* resource_user);
/* Attempts to get quota (from the resource_user) to create 'thd_count' number
* of threads. Returns true if successful (i.e the caller is now free to create
* 'thd_count' number of threads) or false if quota is not available */
bool grpc_resource_user_allocate_threads(grpc_resource_user* resource_user,
int thd_count);
/* Releases 'thd_count' worth of quota back to the resource user. The quota
* should have been previously obtained successfully by calling
* grpc_resource_user_allocate_threads().
*
* Note: There need not be an exact one-to-one correspondence between
* grpc_resource_user_allocate_threads() and grpc_resource_user_free_threads()
* calls. The only requirement is that the number of threads allocated should
* all be eventually released */
void grpc_resource_user_free_threads(grpc_resource_user* resource_user,
int thd_count);
/* Allocate from the resource user (and its quota).
If optional_on_done is NULL, then allocate immediately. This may push the
quota over-limit, at which point reclamation will kick in.

@ -33,4 +33,8 @@ ResourceQuota& ResourceQuota::Resize(size_t new_size) {
return *this;
}
ResourceQuota& ResourceQuota::SetMaxThreads(int new_max_threads) {
grpc_resource_quota_set_max_threads(impl_, new_max_threads);
return *this;
}
} // namespace grpc

@ -261,7 +261,7 @@ std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
}
std::unique_ptr<Server> server(new Server(
max_receive_message_size_, &args, sync_server_cqs,
max_receive_message_size_, &args, sync_server_cqs, resource_quota_,
sync_server_settings_.min_pollers, sync_server_settings_.max_pollers,
sync_server_settings_.cq_timeout_msec));

@ -47,6 +47,12 @@
namespace grpc {
namespace {
// The default value for maximum number of threads that can be created in the
// sync server. This value of 500 is empirically chosen. To increase the max
// number of threads in a sync server, pass a custom ResourceQuota object (with
// the desired number of max-threads set) to the server builder
#define DEFAULT_MAX_SYNC_SERVER_THREADS 500
class DefaultGlobalCallbacks final : public Server::GlobalCallbacks {
public:
~DefaultGlobalCallbacks() override {}
@ -266,9 +272,9 @@ class Server::SyncRequestThreadManager : public ThreadManager {
public:
SyncRequestThreadManager(Server* server, CompletionQueue* server_cq,
std::shared_ptr<GlobalCallbacks> global_callbacks,
int min_pollers, int max_pollers,
int cq_timeout_msec)
: ThreadManager(min_pollers, max_pollers),
grpc_resource_quota* rq, int min_pollers,
int max_pollers, int cq_timeout_msec)
: ThreadManager("SyncServer", rq, min_pollers, max_pollers),
server_(server),
server_cq_(server_cq),
cq_timeout_msec_(cq_timeout_msec),
@ -376,7 +382,8 @@ Server::Server(
int max_receive_message_size, ChannelArguments* args,
std::shared_ptr<std::vector<std::unique_ptr<ServerCompletionQueue>>>
sync_server_cqs,
int min_pollers, int max_pollers, int sync_cq_timeout_msec)
grpc_resource_quota* server_rq, int min_pollers, int max_pollers,
int sync_cq_timeout_msec)
: max_receive_message_size_(max_receive_message_size),
sync_server_cqs_(std::move(sync_server_cqs)),
started_(false),
@ -392,10 +399,22 @@ Server::Server(
global_callbacks_->UpdateArguments(args);
if (sync_server_cqs_ != nullptr) {
bool default_rq_created = false;
if (server_rq == nullptr) {
server_rq = grpc_resource_quota_create("SyncServer-default-rq");
grpc_resource_quota_set_max_threads(server_rq,
DEFAULT_MAX_SYNC_SERVER_THREADS);
default_rq_created = true;
}
for (const auto& it : *sync_server_cqs_) {
sync_req_mgrs_.emplace_back(new SyncRequestThreadManager(
this, it.get(), global_callbacks_, min_pollers, max_pollers,
sync_cq_timeout_msec));
this, it.get(), global_callbacks_, server_rq, min_pollers,
max_pollers, sync_cq_timeout_msec));
}
if (default_rq_created) {
grpc_resource_quota_unref(server_rq);
}
}

@ -22,8 +22,8 @@
#include <mutex>
#include <grpc/support/log.h>
#include "src/core/lib/gprpp/thd.h"
#include "src/core/lib/iomgr/exec_ctx.h"
namespace grpc {
@ -48,12 +48,17 @@ ThreadManager::WorkerThread::~WorkerThread() {
thd_.Join();
}
ThreadManager::ThreadManager(int min_pollers, int max_pollers)
ThreadManager::ThreadManager(const char* name,
grpc_resource_quota* resource_quota,
int min_pollers, int max_pollers)
: shutdown_(false),
num_pollers_(0),
min_pollers_(min_pollers),
max_pollers_(max_pollers == -1 ? INT_MAX : max_pollers),
num_threads_(0) {}
num_threads_(0),
max_active_threads_sofar_(0) {
resource_user_ = grpc_resource_user_create(resource_quota, name);
}
ThreadManager::~ThreadManager() {
{
@ -61,6 +66,8 @@ ThreadManager::~ThreadManager() {
GPR_ASSERT(num_threads_ == 0);
}
grpc_core::ExecCtx exec_ctx; // grpc_resource_user_unref needs an exec_ctx
grpc_resource_user_unref(resource_user_);
CleanupCompletedThreads();
}
@ -81,17 +88,27 @@ bool ThreadManager::IsShutdown() {
return shutdown_;
}
int ThreadManager::GetMaxActiveThreadsSoFar() {
std::lock_guard<std::mutex> list_lock(list_mu_);
return max_active_threads_sofar_;
}
void ThreadManager::MarkAsCompleted(WorkerThread* thd) {
{
std::lock_guard<std::mutex> list_lock(list_mu_);
completed_threads_.push_back(thd);
}
std::lock_guard<std::mutex> lock(mu_);
num_threads_--;
if (num_threads_ == 0) {
shutdown_cv_.notify_one();
{
std::lock_guard<std::mutex> lock(mu_);
num_threads_--;
if (num_threads_ == 0) {
shutdown_cv_.notify_one();
}
}
// Give a thread back to the resource quota
grpc_resource_user_free_threads(resource_user_, 1);
}
void ThreadManager::CleanupCompletedThreads() {
@ -106,14 +123,22 @@ void ThreadManager::CleanupCompletedThreads() {
}
void ThreadManager::Initialize() {
if (!grpc_resource_user_allocate_threads(resource_user_, min_pollers_)) {
gpr_log(GPR_ERROR,
"No thread quota available to even create the minimum required "
"polling threads (i.e %d). Unable to start the thread manager",
min_pollers_);
abort();
}
{
std::unique_lock<std::mutex> lock(mu_);
num_pollers_ = min_pollers_;
num_threads_ = min_pollers_;
max_active_threads_sofar_ = min_pollers_;
}
for (int i = 0; i < min_pollers_; i++) {
// Create a new thread (which ends up calling the MainWorkLoop() function
new WorkerThread(this);
}
}
@ -139,11 +164,15 @@ void ThreadManager::MainWorkLoop() {
done = true;
break;
case WORK_FOUND:
// If we got work and there are now insufficient pollers, start a new
// one
if (!shutdown_ && num_pollers_ < min_pollers_) {
// If we got work and there are now insufficient pollers and there is
// quota available to create a new thread, start a new poller thread
if (!shutdown_ && num_pollers_ < min_pollers_ &&
grpc_resource_user_allocate_threads(resource_user_, 1)) {
num_pollers_++;
num_threads_++;
if (num_threads_ > max_active_threads_sofar_) {
max_active_threads_sofar_ = num_threads_;
}
// Drop lock before spawning thread to avoid contention
lock.unlock();
new WorkerThread(this);
@ -196,6 +225,8 @@ void ThreadManager::MainWorkLoop() {
}
};
// This thread is exiting. Do some cleanup work i.e delete already completed
// worker threads
CleanupCompletedThreads();
// If we are here, either ThreadManager is shutting down or it already has

@ -27,12 +27,14 @@
#include <grpcpp/support/config.h>
#include "src/core/lib/gprpp/thd.h"
#include "src/core/lib/iomgr/resource_quota.h"
namespace grpc {
class ThreadManager {
public:
explicit ThreadManager(int min_pollers, int max_pollers);
explicit ThreadManager(const char* name, grpc_resource_quota* resource_quota,
int min_pollers, int max_pollers);
virtual ~ThreadManager();
// Initializes and Starts the Rpc Manager threads
@ -84,6 +86,11 @@ class ThreadManager {
// all the threads have drained all the outstanding work
virtual void Wait();
// Max number of concurrent threads that were ever active in this thread
// manager so far. This is useful for debugging purposes (and in unit tests)
// to check if resource_quota is properly being enforced.
int GetMaxActiveThreadsSoFar();
private:
// Helper wrapper class around grpc_core::Thread. Takes a ThreadManager object
// and starts a new grpc_core::Thread to calls the Run() function.
@ -91,6 +98,24 @@ class ThreadManager {
// The Run() function calls ThreadManager::MainWorkLoop() function and once
// that completes, it marks the WorkerThread completed by calling
// ThreadManager::MarkAsCompleted()
//
// WHY IS THIS NEEDED?:
// When a thread terminates, some other thread *must* call Join() on that
// thread so that the resources are released. Having a WorkerThread wrapper
// will make this easier. Once Run() completes, each thread calls the
// following two functions:
// ThreadManager::CleanupCompletedThreads()
// ThreadManager::MarkAsCompleted()
//
// - MarkAsCompleted() puts the WorkerThread object in the ThreadManger's
// completed_threads_ list
// - CleanupCompletedThreads() calls "Join()" on the threads that are already
// in the completed_threads_ list (since a thread cannot call Join() on
// itself, it calls CleanupCompletedThreads() *before* calling
// MarkAsCompleted())
//
// TODO(sreek): Consider creating the threads 'detached' so that Join() need
// not be called (and the need for this WorkerThread class is eliminated)
class WorkerThread {
public:
WorkerThread(ThreadManager* thd_mgr);
@ -111,13 +136,21 @@ class ThreadManager {
void MarkAsCompleted(WorkerThread* thd);
void CleanupCompletedThreads();
// Protects shutdown_, num_pollers_ and num_threads_
// TODO: sreek - Change num_pollers and num_threads_ to atomics
// Protects shutdown_, num_pollers_, num_threads_ and
// max_active_threads_sofar_
std::mutex mu_;
bool shutdown_;
std::condition_variable shutdown_cv_;
// The resource user object to use when requesting quota to create threads
//
// Note: The user of this ThreadManager object must create grpc_resource_quota
// object (that contains the actual max thread quota) and a grpc_resource_user
// object through which quota is requested whenver new threads need to be
// created
grpc_resource_user* resource_user_;
// Number of threads doing polling
int num_pollers_;
@ -125,10 +158,15 @@ class ThreadManager {
int min_pollers_;
int max_pollers_;
// The total number of threads (includes threads includes the threads that are
// currently polling i.e num_pollers_)
// The total number of threads currently active (includes threads includes the
// threads that are currently polling i.e num_pollers_)
int num_threads_;
// See GetMaxActiveThreadsSoFar()'s description.
// To be more specific, this variable tracks the max value num_threads_ was
// ever set so far
int max_active_threads_sofar_;
std::mutex list_mu_;
std::list<WorkerThread*> completed_threads_;
};

@ -91,6 +91,7 @@ grpc_resource_quota_create_type grpc_resource_quota_create_import;
grpc_resource_quota_ref_type grpc_resource_quota_ref_import;
grpc_resource_quota_unref_type grpc_resource_quota_unref_import;
grpc_resource_quota_resize_type grpc_resource_quota_resize_import;
grpc_resource_quota_set_max_threads_type grpc_resource_quota_set_max_threads_import;
grpc_resource_quota_arg_vtable_type grpc_resource_quota_arg_vtable_import;
grpc_channelz_get_top_channels_type grpc_channelz_get_top_channels_import;
grpc_channelz_get_channel_type grpc_channelz_get_channel_import;
@ -341,6 +342,7 @@ void grpc_rb_load_imports(HMODULE library) {
grpc_resource_quota_ref_import = (grpc_resource_quota_ref_type) GetProcAddress(library, "grpc_resource_quota_ref");
grpc_resource_quota_unref_import = (grpc_resource_quota_unref_type) GetProcAddress(library, "grpc_resource_quota_unref");
grpc_resource_quota_resize_import = (grpc_resource_quota_resize_type) GetProcAddress(library, "grpc_resource_quota_resize");
grpc_resource_quota_set_max_threads_import = (grpc_resource_quota_set_max_threads_type) GetProcAddress(library, "grpc_resource_quota_set_max_threads");
grpc_resource_quota_arg_vtable_import = (grpc_resource_quota_arg_vtable_type) GetProcAddress(library, "grpc_resource_quota_arg_vtable");
grpc_channelz_get_top_channels_import = (grpc_channelz_get_top_channels_type) GetProcAddress(library, "grpc_channelz_get_top_channels");
grpc_channelz_get_channel_import = (grpc_channelz_get_channel_type) GetProcAddress(library, "grpc_channelz_get_channel");

@ -248,6 +248,9 @@ extern grpc_resource_quota_unref_type grpc_resource_quota_unref_import;
typedef void(*grpc_resource_quota_resize_type)(grpc_resource_quota* resource_quota, size_t new_size);
extern grpc_resource_quota_resize_type grpc_resource_quota_resize_import;
#define grpc_resource_quota_resize grpc_resource_quota_resize_import
typedef void(*grpc_resource_quota_set_max_threads_type)(grpc_resource_quota* resource_quota, int new_max_threads);
extern grpc_resource_quota_set_max_threads_type grpc_resource_quota_set_max_threads_import;
#define grpc_resource_quota_set_max_threads grpc_resource_quota_set_max_threads_import
typedef const grpc_arg_pointer_vtable*(*grpc_resource_quota_arg_vtable_type)(void);
extern grpc_resource_quota_arg_vtable_type grpc_resource_quota_arg_vtable_import;
#define grpc_resource_quota_arg_vtable grpc_resource_quota_arg_vtable_import

@ -798,6 +798,98 @@ static void test_negative_rq_free_pool(void) {
}
}
// Simple test to check resource quota thread limits
static void test_thread_limit() {
grpc_core::ExecCtx exec_ctx;
grpc_resource_quota* rq = grpc_resource_quota_create("test_thread_limit");
grpc_resource_user* ru1 = grpc_resource_user_create(rq, "ru1");
grpc_resource_user* ru2 = grpc_resource_user_create(rq, "ru2");
// Max threads = 100
grpc_resource_quota_set_max_threads(rq, 100);
// Request quota for 100 threads (50 for ru1, 50 for ru2)
GPR_ASSERT(grpc_resource_user_allocate_threads(ru1, 10));
GPR_ASSERT(grpc_resource_user_allocate_threads(ru2, 10));
GPR_ASSERT(grpc_resource_user_allocate_threads(ru1, 40));
GPR_ASSERT(grpc_resource_user_allocate_threads(ru2, 40));
// Threads exhausted. Next request must fail
GPR_ASSERT(!grpc_resource_user_allocate_threads(ru2, 20));
// Free 20 threads from two different users
grpc_resource_user_free_threads(ru1, 10);
grpc_resource_user_free_threads(ru2, 10);
// Next request to 20 threads must succeed
GPR_ASSERT(grpc_resource_user_allocate_threads(ru2, 20));
// No more thread quota again
GPR_ASSERT(!grpc_resource_user_allocate_threads(ru1, 20));
// Free 10 more
grpc_resource_user_free_threads(ru1, 10);
GPR_ASSERT(grpc_resource_user_allocate_threads(ru1, 5));
GPR_ASSERT(
!grpc_resource_user_allocate_threads(ru2, 10)); // Only 5 available
GPR_ASSERT(grpc_resource_user_allocate_threads(ru2, 5));
// Teardown (ru1 and ru2 release all the quota back to rq)
grpc_resource_user_unref(ru1);
grpc_resource_user_unref(ru2);
grpc_resource_quota_unref(rq);
}
// Change max quota in either direction dynamically
static void test_thread_maxquota_change() {
grpc_core::ExecCtx exec_ctx;
grpc_resource_quota* rq =
grpc_resource_quota_create("test_thread_maxquota_change");
grpc_resource_user* ru1 = grpc_resource_user_create(rq, "ru1");
grpc_resource_user* ru2 = grpc_resource_user_create(rq, "ru2");
// Max threads = 100
grpc_resource_quota_set_max_threads(rq, 100);
// Request quota for 100 threads (50 for ru1, 50 for ru2)
GPR_ASSERT(grpc_resource_user_allocate_threads(ru1, 50));
GPR_ASSERT(grpc_resource_user_allocate_threads(ru2, 50));
// Threads exhausted. Next request must fail
GPR_ASSERT(!grpc_resource_user_allocate_threads(ru2, 20));
// Increase maxquota and retry
// Max threads = 150;
grpc_resource_quota_set_max_threads(rq, 150);
GPR_ASSERT(grpc_resource_user_allocate_threads(ru2, 20)); // ru2=70, ru1=50
// Decrease maxquota (Note: Quota already given to ru1 and ru2 is unaffected)
// Max threads = 10;
grpc_resource_quota_set_max_threads(rq, 10);
// New requests will fail until quota is available
GPR_ASSERT(!grpc_resource_user_allocate_threads(ru1, 10));
// Make quota available
grpc_resource_user_free_threads(ru1, 50); // ru1 now has 0
GPR_ASSERT(!grpc_resource_user_allocate_threads(ru1, 10)); // not enough
grpc_resource_user_free_threads(ru2, 70); // ru2 now has 0
// Now we can get quota up-to 10, the current max
GPR_ASSERT(grpc_resource_user_allocate_threads(ru2, 10));
// No more thread quota again
GPR_ASSERT(!grpc_resource_user_allocate_threads(ru1, 10));
// Teardown (ru1 and ru2 release all the quota back to rq)
grpc_resource_user_unref(ru1);
grpc_resource_user_unref(ru2);
grpc_resource_quota_unref(rq);
}
int main(int argc, char** argv) {
grpc_test_init(argc, argv);
grpc_init();
@ -827,6 +919,11 @@ int main(int argc, char** argv) {
test_negative_rq_free_pool();
gpr_mu_destroy(&g_mu);
gpr_cv_destroy(&g_cv);
// Resource quota thread related
test_thread_limit();
test_thread_maxquota_change();
grpc_shutdown();
return 0;
}

@ -130,6 +130,7 @@ int main(int argc, char **argv) {
printf("%lx", (unsigned long) grpc_resource_quota_ref);
printf("%lx", (unsigned long) grpc_resource_quota_unref);
printf("%lx", (unsigned long) grpc_resource_quota_resize);
printf("%lx", (unsigned long) grpc_resource_quota_set_max_threads);
printf("%lx", (unsigned long) grpc_resource_quota_arg_vtable);
printf("%lx", (unsigned long) grpc_channelz_get_top_channels);
printf("%lx", (unsigned long) grpc_channelz_get_channel);

@ -30,30 +30,44 @@
#include "test/cpp/util/test_config.h"
namespace grpc {
struct ThreadManagerTestSettings {
// The min number of pollers that SHOULD be active in ThreadManager
int min_pollers;
// The max number of pollers that could be active in ThreadManager
int max_pollers;
// The sleep duration in PollForWork() function to simulate "polling"
int poll_duration_ms;
// The sleep duration in DoWork() function to simulate "work"
int work_duration_ms;
// Max number of times PollForWork() is called before shutting down
int max_poll_calls;
};
class ThreadManagerTest final : public grpc::ThreadManager {
public:
ThreadManagerTest()
: ThreadManager(kMinPollers, kMaxPollers),
ThreadManagerTest(const char* name, grpc_resource_quota* rq,
const ThreadManagerTestSettings& settings)
: ThreadManager(name, rq, settings.min_pollers, settings.max_pollers),
settings_(settings),
num_do_work_(0),
num_poll_for_work_(0),
num_work_found_(0) {}
grpc::ThreadManager::WorkStatus PollForWork(void** tag, bool* ok) override;
void DoWork(void* tag, bool ok) override;
void PerformTest();
// Get number of times PollForWork() returned WORK_FOUND
int GetNumWorkFound();
// Get number of times DoWork() was called
int GetNumDoWork();
private:
void SleepForMs(int sleep_time_ms);
static const int kMinPollers = 2;
static const int kMaxPollers = 10;
static const int kPollingTimeoutMsec = 10;
static const int kDoWorkDurationMsec = 1;
// PollForWork will return SHUTDOWN after these many number of invocations
static const int kMaxNumPollForWork = 50;
ThreadManagerTestSettings settings_;
// Counters
gpr_atm num_do_work_; // Number of calls to DoWork
gpr_atm num_poll_for_work_; // Number of calls to PollForWork
gpr_atm num_work_found_; // Number of times WORK_FOUND was returned
@ -69,54 +83,117 @@ void ThreadManagerTest::SleepForMs(int duration_ms) {
grpc::ThreadManager::WorkStatus ThreadManagerTest::PollForWork(void** tag,
bool* ok) {
int call_num = gpr_atm_no_barrier_fetch_add(&num_poll_for_work_, 1);
if (call_num >= kMaxNumPollForWork) {
if (call_num >= settings_.max_poll_calls) {
Shutdown();
return SHUTDOWN;
}
// Simulate "polling for work" by sleeping for sometime
SleepForMs(kPollingTimeoutMsec);
SleepForMs(settings_.poll_duration_ms); // Simulate "polling" duration
*tag = nullptr;
*ok = true;
// Return timeout roughly 1 out of every 3 calls
// Return timeout roughly 1 out of every 3 calls just to make the test a bit
// more interesting
if (call_num % 3 == 0) {
return TIMEOUT;
} else {
gpr_atm_no_barrier_fetch_add(&num_work_found_, 1);
return WORK_FOUND;
}
gpr_atm_no_barrier_fetch_add(&num_work_found_, 1);
return WORK_FOUND;
}
void ThreadManagerTest::DoWork(void* tag, bool ok) {
gpr_atm_no_barrier_fetch_add(&num_do_work_, 1);
SleepForMs(kDoWorkDurationMsec); // Simulate doing work by sleeping
SleepForMs(settings_.work_duration_ms); // Simulate work by sleeping
}
void ThreadManagerTest::PerformTest() {
// Initialize() starts the ThreadManager
Initialize();
// Wait for all the threads to gracefully terminate
Wait();
int ThreadManagerTest::GetNumWorkFound() {
return static_cast<int>(gpr_atm_no_barrier_load(&num_work_found_));
}
// The number of times DoWork() was called is equal to the number of times
// WORK_FOUND was returned
gpr_log(GPR_DEBUG, "DoWork() called %" PRIdPTR " times",
gpr_atm_no_barrier_load(&num_do_work_));
GPR_ASSERT(gpr_atm_no_barrier_load(&num_do_work_) ==
gpr_atm_no_barrier_load(&num_work_found_));
int ThreadManagerTest::GetNumDoWork() {
return static_cast<int>(gpr_atm_no_barrier_load(&num_do_work_));
}
} // namespace grpc
// Test that the number of times DoWork() is called is equal to the number of
// times PollForWork() returned WORK_FOUND
static void TestPollAndWork() {
grpc_resource_quota* rq = grpc_resource_quota_create("Test-poll-and-work");
grpc::ThreadManagerTestSettings settings = {
2 /* min_pollers */, 10 /* max_pollers */, 10 /* poll_duration_ms */,
1 /* work_duration_ms */, 50 /* max_poll_calls */};
grpc::ThreadManagerTest test_thread_mgr("TestThreadManager", rq, settings);
grpc_resource_quota_unref(rq);
test_thread_mgr.Initialize(); // Start the thread manager
test_thread_mgr.Wait(); // Wait for all threads to finish
// Verify that The number of times DoWork() was called is equal to the number
// of times WORK_FOUND was returned
gpr_log(GPR_DEBUG, "DoWork() called %d times",
test_thread_mgr.GetNumDoWork());
GPR_ASSERT(test_thread_mgr.GetNumDoWork() ==
test_thread_mgr.GetNumWorkFound());
}
static void TestThreadQuota() {
const int kMaxNumThreads = 3;
grpc_resource_quota* rq = grpc_resource_quota_create("Test-thread-quota");
grpc_resource_quota_set_max_threads(rq, kMaxNumThreads);
// Set work_duration_ms to be much greater than poll_duration_ms. This way,
// the thread manager will be forced to create more 'polling' threads to
// honor the min_pollers guarantee
grpc::ThreadManagerTestSettings settings = {
1 /* min_pollers */, 1 /* max_pollers */, 1 /* poll_duration_ms */,
10 /* work_duration_ms */, 50 /* max_poll_calls */};
// Create two thread managers (but with same resource quota). This means
// that the max number of active threads across BOTH the thread managers
// cannot be greater than kMaxNumthreads
grpc::ThreadManagerTest test_thread_mgr_1("TestThreadManager-1", rq,
settings);
grpc::ThreadManagerTest test_thread_mgr_2("TestThreadManager-2", rq,
settings);
// It is ok to unref resource quota before starting thread managers.
grpc_resource_quota_unref(rq);
// Start both thread managers
test_thread_mgr_1.Initialize();
test_thread_mgr_2.Initialize();
// Wait for both to finish
test_thread_mgr_1.Wait();
test_thread_mgr_2.Wait();
// Now verify that the total number of active threads in either thread manager
// never exceeds kMaxNumThreads
//
// NOTE: Actually the total active threads across *both* thread managers at
// any point of time never exceeds kMaxNumThreads but unfortunately there is
// no easy way to verify it (i.e we can't just do (max1 + max2 <= k))
// Its okay to not test this case here. The resource quota c-core tests
// provide enough coverage to resource quota object with multiple resource
// users
int max1 = test_thread_mgr_1.GetMaxActiveThreadsSoFar();
int max2 = test_thread_mgr_2.GetMaxActiveThreadsSoFar();
gpr_log(
GPR_DEBUG,
"MaxActiveThreads in TestThreadManager_1: %d, TestThreadManager_2: %d",
max1, max2);
GPR_ASSERT(max1 <= kMaxNumThreads && max2 <= kMaxNumThreads);
}
int main(int argc, char** argv) {
std::srand(std::time(nullptr));
grpc::testing::InitTest(&argc, &argv, true);
grpc::ThreadManagerTest test_rpc_manager;
test_rpc_manager.PerformTest();
grpc_init();
TestPollAndWork();
TestThreadQuota();
grpc_shutdown();
return 0;
}

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