If seastar is configured to use hugetlbfs initialize mempools
with external memory buffer. This way we are going to better control the overall
memory consumption.
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
New in v2:
- Use char* instead of void* for pointer's arithmetics.
There is no reason for Rx and Tx pools to be of the same size:
Rx pool is 3 times the ring size to give the upper layers some time
to free the Rx buffers before the ring stalls with no buffers.
Tx has absolutely different constraints: since it provides a back pressure
to the upper layers if HW doesn't keep up there is no need to allow more buffers
in the air than the amount we may send in a single rte_eth_tx_burst() call.
Therefore we need 2 times HW ring size buffers since HW may release the whole
ring of buffers in a single rte_eth_tx_burst() call and thus we may be able to
place another whole ring of buffers in the same call.
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
New in v4:
- Fixed the info message.
httpd uses recursion for its read loop:
future<> read() {
_read_buf.consume().then([] {
...
if more work:
return read();
});
}
However, after error handling was added, it looks like this:
future<> read() {
_read_buf.consume().then([] {
...
if more work:
return read();
}).rescue(...);
}
The problem is that rescue() is called for every iteration of the loop,
instead of for the loop in its entirety. This means that a rescue
continuation is allocated for every processed request, but they will only
be called after the entire loop terminates. This results in tons of
allocated memory.
Fix by moving error handling to the end of the loop (and incidentally using
do_until() instead of recursion).
Size of std::vector<cpu> can be pre-determined, then let's reserve memory ahead
of time so that push back calls would be optimized.
Signed-off-by: Raphael S. Carvalho <raphaelsc@cloudius-systems.com>
If the difference between the sizes of the two strings is larger than can
be represented by an int, truncation will occur and the sign of the result
is undefined.
Fix by using explicit tests and return values.
Add string comparison functions to basic_sstring that are required for
C++ containers such as std::map and std::multimap.
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
This patchs adds a header file, "core/enum.hh"; Code which includes
this header file will be able to use an enumerated type as the key in a
hash table.
The header file implements a hash function for *all* enumerated types,
by using the standard hash function of the underlying integer type.
It is used to recover from a race where the sender is waiting for a
window update and the receiver is waiting for the sender to send more,
because somehow the window update carried in the ACK packet is not seen
by the sender.
This fix tcp_server rxrx test on DPDK. The problem is that when we
receive out of order packets, we will hold the packet in the ooo queue.
We do linearize on the incoming packet which will copy the packet and
thus free the old packet. However, we missed one case where we need to
linearize. As a result, the original packet will be held in the ooo
queue. In DPDK, we have fixed buffer in the rx pool. When all the dpdk
buffer are in ooo queue, we will not be able to receive further packets.
So rx hangs, even ping will not work.
This fix the following:
Server side:
$ tcp_server
Client side:
$ go run client.go -host 192.168.66.123 -conn 10 -test txtx
$ control-c
At this time, connection in tcp_server will be in CLOSED state (reset by
the remote), then tcp_server will call tcp::tcb::close() and wait for
wait_for_all_data_acked(), but no one will signal it. Thus we have tons
of leaked connection in CLOSED state.
We call output_one to make sure a packet with FIN is actually generated
and then sent out. If we only call output() and _packetq is not empty,
in tcp::tcb::get_packet(), packet with FIN will not be generated, thus
we will not send out a FIN.
This can happen when retransmit packets have been queued into _packetq,
then ACK comes which ACK all of the unacked data, then the application
call close() to close the connection.
We currently have RFC5681, a.k.a Reno TCP, as the congestion control
algorithms: slow start, congestion avoidance, fast retransmit, and fast
recovery. RFC6582 describes a specific algorithm for responding to
partial acknowledgments, referred to as NewReno, to improve Reno.
I found wrk sometimes sends RST instead a FIN to close a connection. In
this case, we will reset the connection and go to CLOSED state. However
httpd will not delete this, so we will have leaked connections in CLOSED
state.
Fix by handling the exception and sending an empty response as we do in
EOF case. Here we do not pass the exception to upper layer again,
otherwise httpd will be very noise.
The way periodic timers are rearmed during timer completion causes
timer_settime() to be called twice for each periodic timer completion:
once during rearm and second time by enable_fn(). Fix it by providing
another function that only re-adds timer into timers container, but do
not call timer_settime().
Follow RFC793 section "SEGMENT ARRIVES".
There are 4 major cases:
1) If the state is CLOSED
2) If the state is LISTEN
3) If the state is SYN-SENT
4) If the state is other state
Note:
- This change is significant (more than 10 pages in RFC793 describing
this segment arrival handling).
- More test is needed. Good news is, so far, tcp_server(ping/txtx/rxrx)
tests and httpd work fine.
So that the callback which is set on it and which is allocated on CPU
0 is destroyed on CPU 0 when the clock dies. Otherwise we can attempt
to delete it after the CPU thread is gone if CPU 0 != main thread.
