The following is a list of general existing limitations and known issues of the various components of XLIO. As far as XLIO is inherited from Messaging Accelerator (VMA) 9.2.2 some issues point to (VMA).
Internal Ref. Number | Details |
1542628 | Description: Device memory programming is not supported on VMs that lack Blue Flame support. |
Workaround: N/A | |
Keywords: MEMIC, Device Memory, Virtual Machine, Blue flame | |
Discovered in Version: 1.0.6 | |
— | Description: If XLIO runs when XLIO_HANDLE_SIGINTR is enabled, an error message might be written upon exiting. |
Workaround: Ignore the error message, or run XLIO with XLIO_HANDLE_SIGINTR disabled. | |
Keywords: XLIO_HANDLE_SIGINTR, error message | |
Discovered in Version: 1.0.6 | |
— | Description: The following XLIO_ERRORs will be displayed when running ping with root permissions:XLIO ERROR: ring_simple[0x7f257d18d720]:256:create_resources() ibv_create_comp_channel for tx failed. m_p_tx_comp_event_channel = (nil) (errno=13 Permission denied) |
Workaround: N/A | |
Keywords: XLIO_ERROR while running ping with root permissions | |
Discovered in Version: 1.0.6 | |
965237 | Description: The following sockets APIs are directed to the OS and are not offloaded by XLIO: · int socketpair(int domain, int type, int protocol, int sv[2]); · int dup(int oldfd); · int dup2(int oldfd, int newfd); |
Workaround: N/A | |
Keywords: sockets, socketpair, dup, dup2 | |
965227 | Description: Multicast (MC) loopback within a process is not supported by XLIO:
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Workaround: N/A | |
Keywords: Multicast, Loopback | |
965227 | Description: MC loopback between XLIO and the OS limitation.
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Workaround: N/A | |
Keywords: Multicast, Loopback | |
965227 | Description: MC loopback Tx is currently disabled and setsockopt (IP_MULTICAST_LOOP) is not supported. |
Workaround: N/A | |
Keywords: Multicast, Loopback | |
1011005 | Description: XLIO SELECT option supports up to 200 sockets in TCP. |
Workaround: Use ePoll that supports up to 6000 sockets. | |
Keywords: SockPerf | |
977899 | Description: An unsuccessful trial to connect to a local interface, is reported by XLIO as Connection timeout rather that Connection refused. |
Workaround: N/A | |
Keywords: Verification | |
1019085 | Description: Poll is limited with the amount of sockets. |
Workaround: Use ePoll for large amount of sockets (tested up to 6000) | |
Keywords: Poll, ePoll | |
— | Description: The following XLIO_PANIC will be displayed when there are not enough open files defined on the server:XLIO PANIC : si[fd=1023]:51:sockinfo() failed to create internal epoll (ret=-1 Too many open files |
Workaround: Verify that the number of max open FDs (File Descriptors) in the system (ulimit -n) is twice as number of needed sockets. XLIO internal logic requires one additional FD per offloaded socket. | |
Keywords: XLIO_PANIC while opening large number of sockets | |
— | Description: Applications written in Java use IPv6 by default which is not supported by XLIO and may lead to XLIO not offloading packets |
Workaround: To change Java to work with IPv4, instruct the application to use “Java -Djava.net.preferIPv4Stack=true” | |
Keywords: Java applications using IPv6 stack | |
— | Description: When a XLIO -enabled application is running, there are several cases when it does not exit as expected pressing CTRL-C. |
Workaround: Enable SIGINT handling in XLIO, by using:#export XLIO_HANDLE_SIGINTR=1 | |
Keywords: The XLIO application does not exit when you press CTRL-C. | |
— | Description: XLIO does not support network interface or route changes during runtime |
Workaround: N/A | |
Keywords: Dynamic route or IP changes | |
— | Description: XLIO behavior of epoll EPOLLET (Edge Triggered) and EPOLLOUT flags with TCP sockets differs between OS and XLIO.
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Workaround: N/A | |
Keywords: XLIO behavior of epoll EPOLLET (Edge Triggered) and EPOLLOUT flags with TCP sockets | |
— | Description: XLIO does not close connections located on the same node (sends FIN to peers) when its own process is terminated. |
Workaround: N/A | |
Keywords: XLIO connection | |
— | Description: XLIO is not closed (sends FIN to peers) when its own process is terminated when the /etc/init.d/XLIO is stopped. |
Workaround: Launch /etc/init.d/XLIO start | |
Keywords: XLIO connection | |
— | Description: When a non-offloaded process joins the same MC address as another XLIO process on the same machine, the non-offloaded process does not get any traffic. |
Workaround: Run both processes with XLIO | |
Keywords: MC traffic with XLIO process and non XLIO process on the same machine | |
— | Description: Occasionally, epoll with EPOLLONESHOT does not function properly. |
Workaround: N/A | |
Keywords: epoll with EPOLLONESHOT | |
— | Description: Occasionally, when running UDP SFNT-STREAM client with poll muxer flag, the client-side ends with an expected error:ERROR: Sync messages at end of test lost This only occurs with poll flag |
Workaround: Set a higher acknowledgment waiting time value in the sfnt-stream. | |
Keywords: SFNT-STREAM UDP with poll muxer flag ends with an error on client-side | |
— | Description: Occasionally, SFNT-STREAM UDP client hangs when running multiple times. |
Workaround: Set a higher acknowledgment waiting time value in the sfnt-stream. | |
Keywords: SFNT-STREAM UDP client hanging issue | |
— | Description: Ethernet loopback functions only if both sides are either off-loaded or not-offloaded. |
Workaround: N/A | |
Keywords: Ethernet loopback is not functional between the XLIO and the OS | |
— | Description: The following error may occur when running netperf TCP tests with XLIO:remote error 107 'Transport endpoint is not connected |
Workaround: Use netperf 2.6.0 | |
Keywords: Error when running netperf 2.4.4 with XLIO | |
— | Description: Occasionally, a packet is not sent if the socket is closed immediately after send() (also for blocking socket) |
Workaround: Wait several seconds after send() before closing the socket | |
Keywords: A packet is not sent if the socket is closed immediately after send() | |
— | Description: It can take for XLIO more time than the OS to return from an iomux call if all sockets in this iomux are empty sockets |
Workaround: N/A | |
Keywords: Iomux call with empty sockets | |
— | Description: Sharing of HW resources between the different working threads might cause lock contentions which can affect performance. |
Workaround: Use different ring allocation logic. | |
Keywords: Issues with performance with some multi-threaded applications | |
— | Description: XLIO does not support broadcast traffic. |
Workaround: Use libxlio.conf to pass broadcast through OS | |
Keywords: No support for direct broadcast | |
— | Description: Directing XLIO to access non-valid memory area will cause a segmentation fault. |
Workaround: N/A | |
Keywords: There is no non-valid pointer handling in XLIO | |
— | Description: XLIO allocates resources on the first connect/send operation, which might take up to several tens of milliseconds. |
Workaround: N/A | |
Keywords: First connect/send operation might take more time than expected | |
— | Description: Calling select upon shutdown of socket will return “ready to write” instead of timeout. |
Workaround: N/A | |
Keywords: Calling select() after shutdown (write) returns socket ready to write, while select() is expected to return timeout | |
— | Description: XLIO does not raise sigpipe in connection shutdown. |
Workaround: N/A | |
Keywords: XLIO does not raise sigpipe | |
— | Description: XLIO polls the CQ for packets; if no packets are available in the socket layer, it takes longer. |
Workaround: N/A | |
Keywords: When there are no packets in the socket, it takes longer to return from the read call | |
— | Description: Select with more than 1024 sockets is not supported |
Workaround: Compile XLIO with SELECT_BIG_SETSIZE defined. | |
Keywords: 1024 sockets | |
— | Description: Possible performance degradation running NGINX QUIC. |
Workaround: Use XLIO_CQ_MODERATION_ENABLE=0. | |
Keywords: QUIC, NGINX, XLIO_CQ_MODERATION_ENABLE |