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Diffstat (limited to 'vnet/vnet/policer/police.h')
-rw-r--r-- | vnet/vnet/policer/police.h | 214 |
1 files changed, 0 insertions, 214 deletions
diff --git a/vnet/vnet/policer/police.h b/vnet/vnet/policer/police.h deleted file mode 100644 index 34bcf9ca5a8..00000000000 --- a/vnet/vnet/policer/police.h +++ /dev/null @@ -1,214 +0,0 @@ -/* - * Copyright (c) 2015 Cisco and/or its affiliates. - * 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. - */ -#ifndef __POLICE_H__ -#define __POLICE_H__ - -typedef enum -{ - POLICE_CONFORM = 0, - POLICE_EXCEED = 1, - POLICE_VIOLATE = 2, -} policer_result_e; - -// This is the hardware representation of the policer. -// To be multithread-safe, the policer is accessed through a spin-lock -// on the lock field. (For a policer update operation, 24B needs to be -// modified and this would be a challenge to do with atomic instructions.) -// The structure is padded so that no other data is put into the same -// 64B cache-line. This reduces cache-thrashing between threads. -// -// A note on scale: -// The HW TSC tick is roughly one CPU clock cycle. -// This is shifted to create a larger period, with a goal to be around 50usec. -// The period time will vary based on CPU clock speed. -// CPU speeds of 1Ghz to 8Ghz are targetted. -// The shift amount is a constant 17 bits, resulting in a period between -// 16usec (8Ghz CPU) and 131usec (1Ghz CPU). -// The token_per_period computation takes into account the clock speed. -// -// The 32-bit bucket/limit supports about 850ms of burst on a 40GE port, -// or 340ms on a 100GE port. If a larger burst is configued, then the -// programmed value is simply capped at 2^32-1. If we needed to support -// more than that, the bucket and limit fields could be expanded. -// -// tokens_per_period should be > 1000 to support 0.1% granularity. -// To support lower rates (which would not meet this requirement), the packet -// length, bucket, and limit values can be scaled. The scale is a power of 2 -// so the multiplication can be implemented as a shift. The control plane -// computes the shift amount be the largest possible that still supports the -// burst size. This makes the rate accuracy as high as possible. -// -// The 64-bit last_update_time supports a 4Ghz CPU without rollover for 100 years -// -// The lock field should be used for a spin-lock on the struct. - -#define POLICER_TICKS_PER_PERIOD_SHIFT 17 -#define POLICER_TICKS_PER_PERIOD (1 << POLICER_TICKS_PER_PERIOD_SHIFT) - -typedef struct -{ - - u32 lock; // for exclusive access to the struct - - u32 single_rate; // 1 = single rate policer, 0 = two rate policer - u32 color_aware; // for hierarchical policing - u32 scale; // power-of-2 shift amount for lower rates - u8 action[3]; - u8 mark_dscp[3]; - u8 pad[2]; - - // Fields are marked as 2R if they are only used for a 2-rate policer, - // and MOD if they are modified as part of the update operation. - // 1 token = 1 byte. - - u32 cir_tokens_per_period; // # of tokens for each period - u32 pir_tokens_per_period; // 2R - - u32 current_limit; - u32 current_bucket; // MOD - u32 extended_limit; - u32 extended_bucket; // MOD - - u64 last_update_time; // MOD - u64 pad64; - -} policer_read_response_type_st; - -static inline policer_result_e -vnet_police_packet (policer_read_response_type_st * policer, - u32 packet_length, - policer_result_e packet_color, u64 time) -{ - u64 n_periods; - u64 current_tokens, extended_tokens; - policer_result_e result; - - // Scale packet length to support a wide range of speeds - packet_length = packet_length << policer->scale; - - // Compute the number of policer periods that have passed since the last - // operation. - n_periods = time - policer->last_update_time; - policer->last_update_time = time; - - // Since there is no background last-update-time adjustment, n_periods - // could grow large if the policer is idle for a long time. This could - // cause a 64-bit overflow when computing tokens_per_period * num_periods. - // It will overflow if log2(n_periods) + log2(tokens_per_period) > 64. - // - // To mitigate this, the policer configuration algorithm insures that - // tokens_per_period is less than 2^22, i.e. this is a 22 bit value not - // a 32-bit value. Thus overflow will only occur if n_periods > 64-22 or - // 42. 2^42 min-sized periods is 16us * 2^42, or 2 years. So this can - // rarely occur. If overflow does happen, the only effect will be that - // fewer tokens than the max burst will be added to the bucket for this - // packet. This constraint on tokens_per_period lets the ucode omit - // code to dynamically check for or prevent the overflow. - - if (policer->single_rate) - { - - // Compute number of tokens for this time period - current_tokens = - policer->current_bucket + n_periods * policer->cir_tokens_per_period; - if (current_tokens > policer->current_limit) - { - current_tokens = policer->current_limit; - } - - extended_tokens = - policer->extended_bucket + n_periods * policer->cir_tokens_per_period; - if (extended_tokens > policer->extended_limit) - { - extended_tokens = policer->extended_limit; - } - - // Determine color - - if ((!policer->color_aware || (packet_color == POLICE_CONFORM)) - && (current_tokens >= packet_length)) - { - policer->current_bucket = current_tokens - packet_length; - policer->extended_bucket = extended_tokens - packet_length; - result = POLICE_CONFORM; - } - else if ((!policer->color_aware || (packet_color != POLICE_VIOLATE)) - && (extended_tokens >= packet_length)) - { - policer->current_bucket = current_tokens; - policer->extended_bucket = extended_tokens - packet_length; - result = POLICE_EXCEED; - } - else - { - policer->current_bucket = current_tokens; - policer->extended_bucket = extended_tokens; - result = POLICE_VIOLATE; - } - - } - else - { - // Two-rate policer - - // Compute number of tokens for this time period - current_tokens = - policer->current_bucket + n_periods * policer->cir_tokens_per_period; - extended_tokens = - policer->extended_bucket + n_periods * policer->pir_tokens_per_period; - if (current_tokens > policer->current_limit) - { - current_tokens = policer->current_limit; - } - if (extended_tokens > policer->extended_limit) - { - extended_tokens = policer->extended_limit; - } - - // Determine color - - if ((policer->color_aware && (packet_color == POLICE_VIOLATE)) - || (extended_tokens < packet_length)) - { - policer->current_bucket = current_tokens; - policer->extended_bucket = extended_tokens; - result = POLICE_VIOLATE; - } - else if ((policer->color_aware && (packet_color == POLICE_EXCEED)) - || (current_tokens < packet_length)) - { - policer->current_bucket = current_tokens; - policer->extended_bucket = extended_tokens - packet_length; - result = POLICE_EXCEED; - } - else - { - policer->current_bucket = current_tokens - packet_length; - policer->extended_bucket = extended_tokens - packet_length; - result = POLICE_CONFORM; - } - } - return result; -} - -#endif // __POLICE_H__ - -/* - * fd.io coding-style-patch-verification: ON - * - * Local Variables: - * eval: (c-set-style "gnu") - * End: - */ |