diff options
author | David Howells <dhowells@redhat.com> | 2016-09-22 00:41:53 +0100 |
---|---|---|
committer | David Howells <dhowells@redhat.com> | 2016-09-22 01:26:25 +0100 |
commit | cf1a6474f80735ff4a5d99f3dd68a94dbec8455f (patch) | |
tree | 8ca17608fce76f66375297f2395b0943d8f1e988 /net | |
parent | f07373ead455a396e15a431bc08d8ce1dac6f1cf (diff) | |
download | linux-cf1a6474f80735ff4a5d99f3dd68a94dbec8455f.tar.bz2 |
rxrpc: Add per-peer RTT tracker
Add a function to track the average RTT for a peer. Sources of RTT data
will be added in subsequent patches.
The RTT data will be useful in the future for determining resend timeouts
and for handling the slow-start part of the Rx protocol.
Also add a pair of tracepoints, one to log transmissions to elicit a
response for RTT purposes and one to log responses that contribute RTT
data.
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'net')
-rw-r--r-- | net/rxrpc/ar-internal.h | 25 | ||||
-rw-r--r-- | net/rxrpc/misc.c | 8 | ||||
-rw-r--r-- | net/rxrpc/peer_event.c | 41 |
3 files changed, 70 insertions, 4 deletions
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index dcf54e3fb478..79c671e552c3 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -258,10 +258,11 @@ struct rxrpc_peer { /* calculated RTT cache */ #define RXRPC_RTT_CACHE_SIZE 32 - suseconds_t rtt; /* current RTT estimate (in uS) */ - unsigned int rtt_point; /* next entry at which to insert */ - unsigned int rtt_usage; /* amount of cache actually used */ - suseconds_t rtt_cache[RXRPC_RTT_CACHE_SIZE]; /* calculated RTT cache */ + u64 rtt; /* Current RTT estimate (in nS) */ + u64 rtt_sum; /* Sum of cache contents */ + u64 rtt_cache[RXRPC_RTT_CACHE_SIZE]; /* Determined RTT cache */ + u8 rtt_cursor; /* next entry at which to insert */ + u8 rtt_usage; /* amount of cache actually used */ }; /* @@ -657,6 +658,20 @@ enum rxrpc_recvmsg_trace { extern const char rxrpc_recvmsg_traces[rxrpc_recvmsg__nr_trace][5]; +enum rxrpc_rtt_tx_trace { + rxrpc_rtt_tx_ping, + rxrpc_rtt_tx__nr_trace +}; + +extern const char rxrpc_rtt_tx_traces[rxrpc_rtt_tx__nr_trace][5]; + +enum rxrpc_rtt_rx_trace { + rxrpc_rtt_rx_ping_response, + rxrpc_rtt_rx__nr_trace +}; + +extern const char rxrpc_rtt_rx_traces[rxrpc_rtt_rx__nr_trace][5]; + extern const char *const rxrpc_pkts[]; extern const char *rxrpc_acks(u8 reason); @@ -955,6 +970,8 @@ void rxrpc_reject_packets(struct rxrpc_local *); */ void rxrpc_error_report(struct sock *); void rxrpc_peer_error_distributor(struct work_struct *); +void rxrpc_peer_add_rtt(struct rxrpc_call *, enum rxrpc_rtt_rx_trace, + rxrpc_serial_t, rxrpc_serial_t, ktime_t, ktime_t); /* * peer_object.c diff --git a/net/rxrpc/misc.c b/net/rxrpc/misc.c index 026e1f2e83ff..6321c23f9a6e 100644 --- a/net/rxrpc/misc.c +++ b/net/rxrpc/misc.c @@ -182,3 +182,11 @@ const char rxrpc_recvmsg_traces[rxrpc_recvmsg__nr_trace][5] = { [rxrpc_recvmsg_to_be_accepted] = "TBAC", [rxrpc_recvmsg_return] = "RETN", }; + +const char rxrpc_rtt_tx_traces[rxrpc_rtt_tx__nr_trace][5] = { + [rxrpc_rtt_tx_ping] = "PING", +}; + +const char rxrpc_rtt_rx_traces[rxrpc_rtt_rx__nr_trace][5] = { + [rxrpc_rtt_rx_ping_response] = "PONG", +}; diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c index 18276e7cb9e0..bf13b8470c9a 100644 --- a/net/rxrpc/peer_event.c +++ b/net/rxrpc/peer_event.c @@ -305,3 +305,44 @@ void rxrpc_peer_error_distributor(struct work_struct *work) rxrpc_put_peer(peer); _leave(""); } + +/* + * Add RTT information to cache. This is called in softirq mode and has + * exclusive access to the peer RTT data. + */ +void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why, + rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial, + ktime_t send_time, ktime_t resp_time) +{ + struct rxrpc_peer *peer = call->peer; + s64 rtt; + u64 sum = peer->rtt_sum, avg; + u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage; + + rtt = ktime_to_ns(ktime_sub(resp_time, send_time)); + if (rtt < 0) + return; + + /* Replace the oldest datum in the RTT buffer */ + sum -= peer->rtt_cache[cursor]; + sum += rtt; + peer->rtt_cache[cursor] = rtt; + peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1); + peer->rtt_sum = sum; + if (usage < RXRPC_RTT_CACHE_SIZE) { + usage++; + peer->rtt_usage = usage; + } + + /* Now recalculate the average */ + if (usage == RXRPC_RTT_CACHE_SIZE) { + avg = sum / RXRPC_RTT_CACHE_SIZE; + } else { + avg = sum; + do_div(avg, usage); + } + + peer->rtt = avg; + trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt, + usage, avg); +} |