diff options
| -rw-r--r-- | src/ipcpd/unicast/pol/ca-mb-ecn.c | 123 |
1 files changed, 69 insertions, 54 deletions
diff --git a/src/ipcpd/unicast/pol/ca-mb-ecn.c b/src/ipcpd/unicast/pol/ca-mb-ecn.c index 2de8f8e7..03f7044d 100644 --- a/src/ipcpd/unicast/pol/ca-mb-ecn.c +++ b/src/ipcpd/unicast/pol/ca-mb-ecn.c @@ -37,26 +37,32 @@ #include <string.h> /* congestion avoidance constants */ -#define CA_SHFT 5 -#define CA_WND (1 << CA_SHFT) -#define CA_UPD (1 << (CA_SHFT - 3)) -#define CA_SLOT 18 -#define CA_AI 20000 +#define CA_SHFT 5 /* Average over 32 pkts */ +#define CA_WND (1 << CA_SHFT) /* 32 pkts receiver wnd */ +#define CA_UPD (1 << (CA_SHFT - 3)) /* Update snd every 8 pkt */ +#define CA_SLOT 24 /* Initial slot = 16 ms */ +#define CA_INC 1 << 16 /* ~4MiB/s^2 additive inc */ +#define CA_IWL 1 << 16 /* Initial limit ~4MiB/s */ +#define CA_MINPS 8 /* Mimimum pkts / slot */ +#define CA_MAXPS 64 /* Maximum pkts / slot */ #define ECN_Q_SHFT 5 #define ts_to_ns(ts) (ts.tv_sec * BILLION + ts.tv_nsec) struct mb_ecn_ctx { - uint16_t rx_ece; /* level of congestion (upstream) */ - size_t rx_ctr; /* receiver side packet counter */ - - uint16_t tx_ece; /* level of congestion (downstream) */ - size_t tx_ctr; /* sender side packet counter */ - size_t tx_aps; /* average packet size */ - time_t tx_wnd; /* tgt time to send packets (ns) */ + uint16_t rx_ece; /* Level of congestion (upstream) */ + size_t rx_ctr; /* Receiver side packet counter */ + + uint16_t tx_ece; /* Level of congestion (downstream) */ + size_t tx_ctr; /* Sender side packet counter */ + size_t tx_wbc; /* Window byte count */ + size_t tx_wpc; /* Window packet count */ + size_t tx_wbl; /* Window byte limit */ bool tx_cav; /* Congestion avoidance */ + size_t tx_mul; /* Slot size multiplier */ + size_t tx_inc; /* Additive increase */ size_t tx_slot; - struct timespec t_sent; /* last sent packet */ + struct timespec t_sent; /* Last sent packet */ }; struct pol_ca_ops mb_ecn_ca_ops = { @@ -71,15 +77,22 @@ struct pol_ca_ops mb_ecn_ca_ops = { void * mb_ecn_ctx_create(void) { - + struct timespec now; struct mb_ecn_ctx * ctx; ctx = malloc(sizeof(*ctx)); if (ctx == NULL) return NULL; + clock_gettime(PTHREAD_COND_CLOCK, &now); + memset(ctx, 0, sizeof(*ctx)); + ctx->tx_mul = CA_SLOT; + ctx->tx_wbl = CA_IWL; + ctx->tx_inc = CA_INC; + ctx->tx_slot = ts_to_ns(now) >> ctx->tx_mul; + return (void *) ctx; } @@ -91,54 +104,59 @@ void mb_ecn_ctx_destroy(void * ctx) ca_wnd_t mb_ecn_ctx_update_snd(void * _ctx, size_t len) { - struct timespec now; - size_t slot; - time_t gap; - ca_wnd_t wnd; - + struct timespec now; + size_t slot; + ca_wnd_t wnd; struct mb_ecn_ctx * ctx = _ctx; clock_gettime(PTHREAD_COND_CLOCK, &now); - if (ctx->tx_wnd == 0) { /* 10 ms initial window estimate */ - ctx->tx_wnd = 10 * MILLION; - gap = ctx->tx_wnd >> CA_SHFT; - ctx->tx_aps = len >> CA_SHFT; - ctx->tx_slot = ts_to_ns(now) >> CA_SLOT; - } else { - gap = ts_diff_ns(&ctx->t_sent, &now); - ctx->tx_aps -= ctx->tx_aps >> CA_SHFT; - ctx->tx_aps += len; - } - ctx->t_sent = now; - slot = ts_to_ns(now) >> CA_SLOT; + slot = ts_to_ns(now) >> ctx->tx_mul; ctx->tx_ctr++; + ctx->tx_wpc++; - if (slot - ctx->tx_slot > 0) { - ctx->tx_slot = slot; + if (ctx->tx_ctr > CA_WND) + ctx->tx_ece = 0; - if (ctx->tx_ctr > CA_WND) - ctx->tx_ece = 0; + if (slot > ctx->tx_slot) { + ctx->tx_slot = slot; - /* Slow start */ - if (!ctx->tx_cav) { - ctx->tx_wnd >>= 1; - /* Multiplicative Decrease */ - } else if (ctx->tx_ece) { /* MD */ - ctx->tx_wnd += (ctx->tx_wnd * ctx->tx_ece) + if (!ctx->tx_cav && ctx->tx_wbc > ctx->tx_wbl) /* Slow start */ + ctx->tx_wbl <<= 1; + else if (ctx->tx_ece) /* Multiplicative Decrease */ + ctx->tx_wbl -= (ctx->tx_wbl * ctx->tx_ece) >> (CA_SHFT + 8); - /* Additive Increase */ - } else { - size_t bw = ctx->tx_aps * BILLION / ctx->tx_wnd; - bw += CA_AI; - ctx->tx_wnd = ctx->tx_aps * BILLION / bw; + else /* Additive Increase */ + ctx->tx_wbl = ctx->tx_wbl + ctx->tx_inc; + + /* Window scaling */ + if (ctx->tx_wpc < CA_MINPS) { + ++ctx->tx_mul; + ctx->tx_slot >>= 1; + ctx->tx_wbl <<= 1; + ctx->tx_inc <<= 1; } + + if (ctx->tx_wpc > CA_MAXPS) { + --ctx->tx_mul; /* Underflows at ~CA_MAXPS billion pps */ + ctx->tx_slot <<= 1; + ctx->tx_wbl >>= 1; + ctx->tx_inc >>= 1; + } + + ctx->tx_wbc = 0; + ctx->tx_wpc = 0; } - wnd.wait = (ctx->tx_wnd >> CA_SHFT) - gap; + ctx->tx_wbc += len; + + if (ctx->tx_wbc > ctx->tx_wbl) + wnd.wait = ((ctx->tx_slot + 1) << ctx->tx_mul) - ts_to_ns(now); + else + wnd.wait = 0; return wnd; } @@ -147,7 +165,7 @@ void mb_ecn_wnd_wait(ca_wnd_t wnd) { if (wnd.wait > 0) { struct timespec s = {0, 0}; - if (wnd.wait > BILLION) /* Don't care throttling < 1pps */ + if (wnd.wait > BILLION) /* Don't care throttling < 1s */ s.tv_sec = 1; else s.tv_nsec = wnd.wait; @@ -169,18 +187,15 @@ bool mb_ecn_ctx_update_rcv(void * _ctx, if ((ctx->rx_ece | ecn) == 0) return false; - if (ecn == 0) { - /* end of congestion */ + if (ecn == 0) { /* End of congestion */ ctx->rx_ece >>= 2; update = ctx->rx_ece == 0; } else { - if (ctx->rx_ece == 0) { - /* start of congestion */ + if (ctx->rx_ece == 0) { /* Start of congestion */ ctx->rx_ece = ecn; ctx->rx_ctr = 0; update = true; - } else { - /* congestion update */ + } else { /* Congestion update */ ctx->rx_ece -= ctx->rx_ece >> CA_SHFT; ctx->rx_ece += ecn; update = (ctx->rx_ctr++ & (CA_UPD - 1)) == true; |