International Business Machines Corporation

John Bruce Carter

Kanak Behari Agarwal

Wesley Michael Felter

Karthick Rajamani

Yu Gu

Eric Rozner

Keqiang He

Colin Kimm Dixon

Wei T Huang

Malcolm Scott Ware

Elmootazbellah Nabil Elnozahy

Lixin Zhang

William Evan Speight

Jeffrey A Stuecheli

Freeman Leigh Rawson, Iii

Charles Robert Lefurgy

Malcolm Scott Allen-Ware

Heather Lynn Hanson

Jeffrey Thomas Rasley

Bruce Gerard Mealey

Eric Eugene Retter

Anthony N Hylick

Madhusudan K Iyengar

Ahmed Gheith

Jian Li

Juan C Rubio

Guillermo Jesus Silva

Wael R El-Essawy

Thomas W Keller, Jr

Kshitij Sudan

Eric Van Hansbergen

Ankit Singla

Michael Stephen Floyd

Harigovind Venkatraj Ramasamy

Alan J Drake

Gregory Scott Still

Todd Jon Rosedahl

Bishop Chapman Brock

Malcom S Ware

Brent E Stephens

A processor may receive information about one or more environmental factors. The processor may predict, based on the one or more environmental factors, that a particular datacenter in a distributed computing environment will experience elevated bit-flip error rates during a certain time period. The processor may select, based on the predicted elevated bit-flip error rates, one or more specific applications in the particular datacenter to be protected. The processor may protect the selected one or more specific applications during the certain time period of the predicted elevated bit-flip rates.

Application protection from bit-flip effects

At an application executing in conjunction with a vSwitch in a host system, using a processor assigned to the vSwitch in the host system, a flow of a number of packets is received from a VM. At the application, a set of CWND values is computed using a corresponding set of congestion control algorithms. At the application, a determination is made whether any of the CWND values in the set of CWND values match the number of packets in the flow within a tolerance value. In response to a CWND value in the set of CWND matching the number of packets in the flow within the tolerance value, a conclusion is drawn that a type of the congestion control algorithm which computed the matching CWND value is the type of a local congestion control algorithm implemented within the VM.

Identifying a local congestion control algorithm of a virtual machine

At an application executing in conjunction with a vSwitch a determination is made that a first flow from a first VM is experiencing congestion. The first flow is selected for throttling. a second flow is also selected for throttling, the second flow using a portion of a network path used by the first flow in a data network. At the application, a total CWND adjustment is distributed between the first flow and the second flow. A first CWND value associated with the first flow is adjusted by a first portion of the total CWND window, and a second CWND value associated with the second flow is adjusted by a second portion of the total CWND window.

Virtual switch-based congestion control for multiple TCP flows

A timer is associated with a packet of a flow from a VM at an application executing in conjunction with a vSwitch in a host system, using a processor assigned to the vSwitch in the host system. At the application, using a counter, a number of packets of the flow that are received and acknowledged in response packets is counted, the response packets being received from a receiver of the flow. At the application, using a period measured by the timer and the number of received packets acknowledged as counted by the counter, a CWND value is computed. The CWND value is applied to the flow at the vSwitch such that the vSwitch transmits, from the flow to a network, only a number of packets up to the CWND value.

Virtual switch-based congestion control for datacenter networks

At an application executing in conjunction with a vSwitch in a host system, a CWND value is computed corresponding to a flow from a VM using a period measured by a timer and a number of packets of the flow received and acknowledged in response packets, the number being counted by a counter, the timer being associated with a packet of the flow. The CWND value is stored in a field in a response packet received from a receiver of the flow, the field being designated for carrying a RWND value, the response packet corresponding to a packet in the flow. The storing forms a modified response packet.

Enforcing datacenter-level congestion control

At an application executing in conjunction with a vSwitch in a host system, using a processor assigned to the vSwitch in the host system, a CWND value corresponding to a flow from a VM is computed using a period measured by a timer and a number of packets of the flow received and acknowledged in response packets, the number being counted by a counter, the timer being associated with a packet of the flow. A set of flow parameters is extracted, at the application, from the flow. At the application, a normalized value corresponding to the flow is computed. At the application, the CWND value is reduced according to the normalized value of the flow to form a reduced CWND value. The reduced CWND value is applied to the flow at the vSwitch such that the vSwitch transmits, from the flow to a network, only a number of packets up to the reduced CWND value.

Normalized flow value-based congestion control

A method, system, and computer program product for on-chip control of thermal cycling in an integrated circuit (IC) are provided in the illustrative embodiments. A first circuit is configured on the IC for adjusting a first voltage being applied to a first part of the IC. A first temperature of the first part is measured at a first time. A determination is made that the first temperature is outside a temperature range defined by an upper temperature threshold and a lower temperature threshold. The first voltage is adjusted by reducing the first voltage when the first temperature exceeds the upper temperature threshold and by increasing the first voltage when the first temperature is below the lower temperature threshold, thereby causing the first temperature of the first part to attain a value within the temperature range.

On-chip control of thermal cycling

Mechanisms are provided for determining an event rate. The mechanisms sample a sequence of events to generate a set of sampled events. At least a subset of the sampled events have associated event sequence values indicating a position of the sampled event within the sequence of events. The mechanisms group the sampled events into a plurality of event groups based on a common characteristic of the events. The mechanisms determine, for each event group, sequence values of sampled events associated with the event group. The mechanisms calculate, for each event group, an estimated event rate based on the sequence values of the sampled events associated with the event group and the total number of events in the sequence of events.

Determining sampling rate from randomly sampled events

At an application executing in conjunction with a vSwitch in a host system, using a processor assigned to the vSwitch in the host system, a CWND value is computed corresponding to a flow from a VM using a period measured by a timer and a number of packets of the flow received and acknowledged in response packets, the number being counted by a counter, the timer being associated with a packet of the flow. The CWND value is stored in a field in a response packet received from a receiver of the flow, the field being designated for carrying a RWND value, the response packet corresponding to a packet in the flow. The storing forms a modified response packet. The modified response packet is sent from the vSwitch to the VM.

A system, and computer usable program product for fast remote communication and computation between processors are provided in the illustrative embodiments. A direct core to core communication unit (DCC) is configured to operate with a first processor, the first processor being a remote processor. A memory associated with the DCC receives a set of bytes, the set of bytes being sent from a second processor. An operation specified in the set of bytes is executed at the remote processor such that the operation is invoked without causing a software thread to execute.

Fast remote communication and computation between processors using store and load operations on direct core-to-core memory

Mechanisms are provided for analyzing data traffic through a network. The mechanisms sample data packets of a data flow through a normal port of a network forwarding device of the network. The sampling is performed at least by configuring the network forwarding device to implement port mirroring of the normal port to a designated mirror port of the network forwarding device. The mechanisms forward sampled data packets, copied to the mirror port by virtue of the port mirroring, to a collector computing device. The mechanisms process, by the collector computing device, the sampled data packets to analyze the data flow through the normal port of the network forwarding device. The mechanisms perform, by the collector computing device, an operation based on results of the analysis.

Port mirroring for sampling measurement of network flows

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Austin, TX, United States of America

John Bruce Carter