mirror of https://github.com/grpc/grpc.git
Mark D. Roth
8 years ago
parent
bf1eb38ced
commit
d6d192d005
22 changed files with 496 additions and 6 deletions
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/*
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* |
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* Copyright 2017, Google Inc. |
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* All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions are |
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* met: |
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* |
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* * Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* * Redistributions in binary form must reproduce the above |
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* copyright notice, this list of conditions and the following disclaimer |
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* in the documentation and/or other materials provided with the |
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* distribution. |
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* * Neither the name of Google Inc. nor the names of its |
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* contributors may be used to endorse or promote products derived from |
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* this software without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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* |
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*/ |
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#include "src/core/ext/client_channel/retry_throttle.h" |
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#include <limits.h> |
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#include <string.h> |
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#include <grpc/support/alloc.h> |
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#include <grpc/support/atm.h> |
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#include <grpc/support/avl.h> |
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#include <grpc/support/string_util.h> |
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#include <grpc/support/sync.h> |
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//
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// server_retry_throttle_data
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//
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struct grpc_server_retry_throttle_data { |
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gpr_refcount refs; |
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int max_milli_tokens; |
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int milli_token_ratio; |
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gpr_atm milli_tokens; |
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// A pointer to the replacement for this grpc_server_retry_throttle_data
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// entry. If non-NULL, then this entry is stale and must not be used.
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// We hold a reference to the replacement.
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gpr_atm replacement; |
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}; |
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static void get_replacement_throttle_data_if_needed( |
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grpc_server_retry_throttle_data** throttle_data) { |
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while (true) { |
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grpc_server_retry_throttle_data* new_throttle_data = |
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(grpc_server_retry_throttle_data*)gpr_atm_acq_load( |
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&(*throttle_data)->replacement); |
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if (new_throttle_data == NULL) return; |
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// Reset *throttle_data to its replacement, updating refcounts as
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// appropriate.
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// Note: It's safe to do this here, because the caller ensures that
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// this will only be called with a given value of throttle_data from
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// one thread at a time.
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grpc_server_retry_throttle_data_ref(new_throttle_data); |
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grpc_server_retry_throttle_data* old_throttle_data = *throttle_data; |
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*throttle_data = new_throttle_data; |
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grpc_server_retry_throttle_data_unref(old_throttle_data); |
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} |
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} |
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bool grpc_server_retry_throttle_data_record_failure( |
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grpc_server_retry_throttle_data** throttle_data) { |
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// First, check if we are stale and need to be replaced.
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get_replacement_throttle_data_if_needed(throttle_data); |
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// We decrement milli_tokens by 1000 (1 token) for each failure.
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const int delta = -1000; |
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const int old_value = (int)gpr_atm_full_fetch_add( |
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&(*throttle_data)->milli_tokens, (gpr_atm)delta); |
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// If the above change takes us below 0, then re-add the excess. Note
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// that between these two atomic operations, the value will be
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// artificially low by as much as 1000, but this window should be
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// brief.
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int new_value = old_value - 1000; |
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if (new_value < 0) { |
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const int excess_value = new_value - (old_value < 0 ? old_value : 0); |
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gpr_atm_full_fetch_add(&(*throttle_data)->milli_tokens, |
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(gpr_atm)-excess_value); |
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new_value = 0; |
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} |
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// Retries are allowed as long as the new value is above the threshold
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// (max_milli_tokens / 2).
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return new_value > (*throttle_data)->max_milli_tokens / 2; |
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} |
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void grpc_server_retry_throttle_data_record_success( |
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grpc_server_retry_throttle_data** throttle_data) { |
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// First, check if we are stale and need to be replaced.
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get_replacement_throttle_data_if_needed(throttle_data); |
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// We increment milli_tokens by milli_token_ratio for each success.
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const int delta = (*throttle_data)->milli_token_ratio; |
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const int old_value = (int)gpr_atm_full_fetch_add( |
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&(*throttle_data)->milli_tokens, (gpr_atm)delta); |
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// If the above change takes us over max_milli_tokens, then subtract
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// the excess. Note that between these two atomic operations, the
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// value will be artificially high by as much as milli_token_ratio,
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// but this window should be brief.
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const int new_value = old_value + (*throttle_data)->milli_token_ratio; |
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if (new_value > (*throttle_data)->max_milli_tokens) { |
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const int excess_value = |
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new_value - (old_value > (*throttle_data)->max_milli_tokens |
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? old_value |
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: (*throttle_data)->max_milli_tokens); |
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gpr_atm_full_fetch_add(&(*throttle_data)->milli_tokens, |
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(gpr_atm)-excess_value); |
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} |
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} |
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void grpc_server_retry_throttle_data_ref( |
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grpc_server_retry_throttle_data* throttle_data) { |
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gpr_ref(&throttle_data->refs); |
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} |
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void grpc_server_retry_throttle_data_unref( |
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grpc_server_retry_throttle_data* throttle_data) { |
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if (gpr_unref(&throttle_data->refs)) { |
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grpc_server_retry_throttle_data* replacement = |
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(grpc_server_retry_throttle_data*)gpr_atm_acq_load( |
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&throttle_data->replacement); |
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if (replacement != NULL) { |
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grpc_server_retry_throttle_data_unref(replacement); |
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} |
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gpr_free(throttle_data); |
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} |
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} |
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static grpc_server_retry_throttle_data* grpc_server_retry_throttle_data_create( |
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int max_milli_tokens, int milli_token_ratio, |
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grpc_server_retry_throttle_data* old_throttle_data) { |
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grpc_server_retry_throttle_data* throttle_data = |
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gpr_malloc(sizeof(*throttle_data)); |
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memset(throttle_data, 0, sizeof(*throttle_data)); |
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gpr_ref_init(&throttle_data->refs, 1); |
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throttle_data->max_milli_tokens = max_milli_tokens; |
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throttle_data->milli_token_ratio = milli_token_ratio; |
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int initial_milli_tokens = max_milli_tokens; |
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// If there was a pre-existing entry for this server name, initialize
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// the token count by scaling proportionately to the old data. This
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// ensures that if we're already throttling retries on the old scale,
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// we will start out doing the same thing on the new one.
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if (old_throttle_data != NULL) { |
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double token_fraction = |
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(int)gpr_atm_acq_load(&old_throttle_data->milli_tokens) / |
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(double)old_throttle_data->max_milli_tokens; |
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initial_milli_tokens = (int)(token_fraction * max_milli_tokens); |
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} |
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gpr_atm_rel_store(&throttle_data->milli_tokens, |
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(gpr_atm)initial_milli_tokens); |
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// If there was a pre-existing entry, mark it as stale and give it a
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// pointer to the new entry, which is its replacement.
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if (old_throttle_data != NULL) { |
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grpc_server_retry_throttle_data_ref(throttle_data); |
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gpr_atm_rel_store(&old_throttle_data->replacement, (gpr_atm)throttle_data); |
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} |
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return throttle_data; |
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} |
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//
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// avl vtable for string -> server_retry_throttle_data map
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//
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static void* copy_server_name(void* key) { return gpr_strdup(key); } |
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static long compare_server_name(void* key1, void* key2) { |
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return strcmp(key1, key2); |
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} |
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static void destroy_server_retry_throttle_data(void* value) { |
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grpc_server_retry_throttle_data* throttle_data = value; |
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grpc_server_retry_throttle_data_unref(throttle_data); |
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} |
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static void* copy_server_retry_throttle_data(void* value) { |
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grpc_server_retry_throttle_data* throttle_data = value; |
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grpc_server_retry_throttle_data_ref(throttle_data); |
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return value; |
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} |
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static const gpr_avl_vtable avl_vtable = { |
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gpr_free /* destroy_key */, copy_server_name, compare_server_name, |
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destroy_server_retry_throttle_data, copy_server_retry_throttle_data}; |
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//
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// server_retry_throttle_map
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//
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static gpr_mu g_mu; |
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static gpr_avl g_avl; |
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void grpc_retry_throttle_map_init() { |
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gpr_mu_init(&g_mu); |
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g_avl = gpr_avl_create(&avl_vtable); |
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} |
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void grpc_retry_throttle_map_shutdown() { |
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gpr_mu_destroy(&g_mu); |
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gpr_avl_unref(g_avl); |
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} |
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grpc_server_retry_throttle_data* grpc_retry_throttle_map_get_data_for_server( |
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const char* server_name, int max_milli_tokens, int milli_token_ratio) { |
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gpr_mu_lock(&g_mu); |
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grpc_server_retry_throttle_data* throttle_data = |
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gpr_avl_get(g_avl, (char*)server_name); |
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if (throttle_data == NULL) { |
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// Entry not found. Create a new one.
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throttle_data = grpc_server_retry_throttle_data_create( |
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max_milli_tokens, milli_token_ratio, NULL); |
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g_avl = gpr_avl_add(g_avl, (char*)server_name, throttle_data); |
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} else { |
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if (throttle_data->max_milli_tokens != max_milli_tokens || |
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throttle_data->milli_token_ratio != milli_token_ratio) { |
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// Entry found but with old parameters. Create a new one based on
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// the original one.
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throttle_data = grpc_server_retry_throttle_data_create( |
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max_milli_tokens, milli_token_ratio, throttle_data); |
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g_avl = gpr_avl_add(g_avl, (char*)server_name, throttle_data); |
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} else { |
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// Entry found. Increase refcount.
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grpc_server_retry_throttle_data_ref(throttle_data); |
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} |
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} |
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gpr_mu_unlock(&g_mu); |
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return throttle_data; |
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} |
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@ -0,0 +1,69 @@ |
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/*
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* |
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* Copyright 2017, Google Inc. |
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* All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions are |
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* met: |
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* |
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* * Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* * Redistributions in binary form must reproduce the above |
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* copyright notice, this list of conditions and the following disclaimer |
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* in the documentation and/or other materials provided with the |
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* distribution. |
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* * Neither the name of Google Inc. nor the names of its |
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* contributors may be used to endorse or promote products derived from |
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* this software without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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* |
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*/ |
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#ifndef GRPC_CORE_EXT_CLIENT_CHANNEL_RETRY_THROTTLE_H |
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#define GRPC_CORE_EXT_CLIENT_CHANNEL_RETRY_THROTTLE_H |
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#include <stdbool.h> |
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/// Tracks retry throttling data for an individual server name.
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typedef struct grpc_server_retry_throttle_data grpc_server_retry_throttle_data; |
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/// Records a failure. Returns true if it's okay to send a retry.
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/// Updates \a throttle_data if the original value is stale and has been
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/// replaced. Not thread safe; caller must synchronize.
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bool grpc_server_retry_throttle_data_record_failure( |
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grpc_server_retry_throttle_data** throttle_data); |
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/// Records a success.
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/// Updates \a throttle_data if the original value is stale and has been
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/// replaced. Not thread safe; caller must synchronize.
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void grpc_server_retry_throttle_data_record_success( |
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grpc_server_retry_throttle_data** throttle_data); |
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void grpc_server_retry_throttle_data_ref( |
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grpc_server_retry_throttle_data* throttle_data); |
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void grpc_server_retry_throttle_data_unref( |
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grpc_server_retry_throttle_data* throttle_data); |
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/// Initializes global map of failure data for each server name.
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void grpc_retry_throttle_map_init(); |
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/// Shuts down global map of failure data for each server name.
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void grpc_retry_throttle_map_shutdown(); |
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/// Returns a reference to the failure data for \a server_name, creating
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/// a new entry if needed.
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/// Caller must eventually unref via \a grpc_server_retry_throttle_data_unref().
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grpc_server_retry_throttle_data* grpc_retry_throttle_map_get_data_for_server( |
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const char* server_name, int max_milli_tokens, int milli_token_ratio); |
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#endif /* GRPC_CORE_EXT_CLIENT_CHANNEL_RETRY_THROTTLE_H */ |
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