diff options
| author |  Yuchen Zeng <zyc@google.com> | 2017-03-30 15:31:29 -0700 |
|---|---|---|
| committer | Yuchen Zeng <zyc@google.com> | 2017-04-04 13:56:47 -0700 |
| commit | a2ca7247ae7345dce987a3542a816f4e101a9345 (patch) | |
| tree | 142150bbf9ef8a37a21dc3ed2d0a6ce8f39eb8db /src | |
| parent | ca38800d6236835d3907b8c29e6faeebe31ffeb7 (diff) | |
Add max_connection_age jitter
Diffstat (limited to 'src')
| -rw-r--r-- | src/core/ext/filters/max_age/max_age_filter.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/src/core/ext/filters/max_age/max_age_filter.c b/src/core/ext/filters/max_age/max_age_filter.c index b03cb0ba0a..be5350bce5 100644 --- a/src/core/ext/filters/max_age/max_age_filter.c +++ b/src/core/ext/filters/max_age/max_age_filter.c @@ -46,6 +46,7 @@ #define DEFAULT_MAX_CONNECTION_AGE_MS INT_MAX #define DEFAULT_MAX_CONNECTION_AGE_GRACE_MS INT_MAX #define DEFAULT_MAX_CONNECTION_IDLE_MS INT_MAX +#define MAX_CONNECTION_AGE_JITTER 0.1 typedef struct channel_data { /* We take a reference to the channel stack for the timer callback */ @@ -254,6 +255,19 @@ static void channel_connectivity_changed(grpc_exec_ctx* exec_ctx, void* arg, } } +/* A random jitter of +/-10% will be added to MAX_CONNECTION_AGE to spread out + connection storms. Note that the MAX_CONNECTION_AGE option without jitter + would not create connection storms by itself, but if there happened to be a + connection storm it could cause it to repeat at a fixed period. */ +static int add_random_max_connection_age_jitter(int value) { + /* generate a random number between 1 - MAX_CONNECTION_AGE_JITTER and + 1 + MAX_CONNECTION_AGE_JITTER */ + double multiplier = rand() * MAX_CONNECTION_AGE_JITTER * 2.0 / RAND_MAX + + 1.0 - MAX_CONNECTION_AGE_JITTER; + double result = multiplier * value; + return result > INT_MAX ? INT_MAX : (int)result; +} + /* Constructor for call_data. */ static grpc_error* init_call_elem(grpc_exec_ctx* exec_ctx, grpc_call_element* elem, @@ -283,7 +297,9 @@ static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx, chand->max_connection_age = DEFAULT_MAX_CONNECTION_AGE_MS == INT_MAX ? gpr_inf_future(GPR_TIMESPAN) - : gpr_time_from_millis(DEFAULT_MAX_CONNECTION_AGE_MS, GPR_TIMESPAN); + : gpr_time_from_millis(add_random_max_connection_age_jitter( + DEFAULT_MAX_CONNECTION_AGE_MS), + GPR_TIMESPAN); chand->max_connection_age_grace = DEFAULT_MAX_CONNECTION_AGE_GRACE_MS == INT_MAX ? gpr_inf_future(GPR_TIMESPAN) @@ -300,8 +316,10 @@ static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx, &args->channel_args->args[i], (grpc_integer_options){DEFAULT_MAX_CONNECTION_AGE_MS, 1, INT_MAX}); chand->max_connection_age = - value == INT_MAX ? gpr_inf_future(GPR_TIMESPAN) - : gpr_time_from_millis(value, GPR_TIMESPAN); + value == INT_MAX + ? gpr_inf_future(GPR_TIMESPAN) + : gpr_time_from_millis( + add_random_max_connection_age_jitter(value), GPR_TIMESPAN); } else if (0 == strcmp(args->channel_args->args[i].key, GRPC_ARG_MAX_CONNECTION_AGE_GRACE_MS)) { const int value = grpc_channel_arg_get_integer( |