FlexTOE is a flexible, yet high-performance TCP offload engine (TOE) to SmartNICs. FlexTOE eliminates almost all host data-path TCP processing and is fully customizable. FlexTOE interoperates well with other TCP stacks, is robust under adverse network conditions, and supports POSIX sockets.
FlexTOE focuses on data-path offload of established connections, avoiding complex control logic and packet buffering in the NIC. FlexTOE leverages fine-grained parallelization of the TCP data-path and segment reordering for high performance on wimpy SmartNIC architectures, while remaining flexible via a modular design. We compare FlexTOE on an Agilio-CX40 to host TCP stacks Linux and TAS, and to the Chelsio Terminator TOE. We find that Memcached scales up to 38% better on FlexTOE versus TAS, while saving up to 81% host CPU cycles versus Chelsio. FlexTOE provides competitive performance for RPCs, even with wimpy SmartNICs. FlexTOE cuts 99.99th-percentile RPC RTT by 3.2× and 50% versus Chelsio and TAS, respectively. FlexTOE's data-path parallelism generalizes across hardware architectures, improving single connection RPC throughput up to 2.4× on x86 and 4× on BlueField. FlexTOE supports C and XDP programs written in eBPF. It allows us to implement popular data center transport features, such as TCP tracing, packet filtering and capture, VLAN stripping, flow classification, firewalling, and connection splicing.
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TAS: TCP Acceleration as an OS Service
As datacenter network speeds rise, an increasing fraction of server CPU cycles is consumed by TCP packet processing, in particular for remote procedure calls (RPCs). To free server CPUs from this burden, various existing approaches have attempted to mitigate these overheads, by bypassing the OS kernel, customizing the TCP stack for an application, or by offloading packet processing to dedicated hardware. In doing so, these approaches trade security, agility, or generality for efficiency. Neither trade-off is fully desirable in the fast-evolving commodity cloud.
We present TAS, TCP acceleration as a service. TAS splits the common case of TCP processing for RPCs in the datacenter from the OS kernel and executes it as a fastpath OS service on dedicated CPUs. Doing so allows us to streamline the common case, while still supporting all of the features of a stock TCP stack, including security, agility, and generality. In particular, we remove code and data of less common cases from the fastpath, improving performance on the wide, deeply pipelined CPU architecture common in today's servers. To be workload proportional, TAS dynamically allocates the appropriate amount of CPUs to accommodate the fastpath, depending on the traffic load. TAS provides up to 90% higher throughput and 57% lower tail latency than the IX kernel bypass OS for common cloud applications, such as a key-value store and a realtime analytics framework. TAS also scales to more TCP connections, providing 2.2x higher throughput than IX with 64K connections.
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- Award ID(s):
- 1751231
- NSF-PAR ID:
- 10126683
- Date Published:
- Journal Name:
- Proceedings of the Fourteenth EuroSys Conference 2019
- Page Range / eLocation ID:
- 1 to 16
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1145/3302424.3303985
