International Business Machines Corporation

Kiet Hien Lam

Venkat Venkatsubra

Herman Dietrich Dierks

Vinit Jain

Kavitha V M Baratakke

Vasu Vallabhaneni

James Brian Cunningham

Octavian Florin Herescu

Men-Chow Chiang

Ranadip Das

Bernard A King-Smith

Jose Raul Escalera

Andres Herrera

Mechanisms for controlling rollover or reset of hardware performance counters in the data processing system. A signal indicating that a rollover or reset of a first hardware performance counter has occurred is received and it is determined if the first hardware performance counter is analytically related to one or more second hardware performance counters based on defined ganged hardware performance counter sets. A signal is sent to each of the one or more second hardware performance counters in response to a determination that the first hardware performance counter is analytically related to the one or more second hardware performance counters. Each of the one or more second hardware performance counters is reset to an initial value in response to the one or more second hardware performance counters receiving the signal from the ganged hardware performance counter rollover/reset logic.

Ganged hardware counters for coordinated rollover and reset operations

A system, method, and program product is provided that requests, by a first computer system, a new network session with a second computer system. The new network session request occurs after a previous network session between the two systems and the new network session request includes a new sequence number that is different from a previous sequence number that was used during the previous network session. The first computer system receives an acknowledgement from the second computer system that references the previous sequence number instead of the new sequence number. In response to receiving the acknowledgement at the first computer system that references the previous sequence number, the first computer system modifies the new sequence number by setting it to a value that is higher than the previous sequence number, and the first computer system re-requests the new network session using the modified new sequence number.

System and method for minimizing retry delays in high traffic computer networks

The present invention provides receiving and transmitting devices for providing fragmentation at a transport level along a transmission path. The transmitting device comprises an interface and a control unit coupled to the interface. The control unit is adapted to negotiate a packet size with a remote device. The control unit is also adapted to transmit a data packet of up to the negotiated size. The control unit is further adapted to receive acknowledgments from the remote device associated with one or more fragments, fragmented at the transport-level, of the transmitted data packet. The receiving device comprises an interface and a control unit coupled to the interface. The control unit is adapted to receive two or more fragments of a data packet transmitted by a remote device. The control unit is also adapted to transmit one or more acknowledgments to the remote device based on the received fragments.

Receiving and transmitting devices for providing fragmentation at a transport level along a transmission path

A method for virtual segmentation off-load in a logically partitioned data processing system is provided. A data transmission protocol stack formats a data message for segmentation off-load to form a virtual segmentation off-load package. The size of the data message is larger than a size of a maximum transmission unit. A partition manager firmware copies the virtual segmentation off-load package from a first logical partition to a virtual Ethernet adapter associated with a second logical partition. The virtual segmentation off-load package is copied without performing a segmentation operation on the data message associated with the virtual segmentation off-load package.

Method and apparatus to perform segmentation off-load between two logical partitions

Mechanisms for reducing memory overhead of a page table in a dynamic logical partitioning (LPAR) environment are provided. Each LPAR, upon its creation, is allowed to declare any maximum main memory size for the LPAR as long as the aggregate maximum main memory size for all LPARs does not exceed the total amount of available main memory. A single page table is used for all of the LPARs. Thus, the only page table in the computing system is shared by all LPARs and every memory access operation from any LPAR must go through the same page table for address translation. As a result, since only one page table is utilized, and the aggregate size of the main memory apportioned to each of the LPARs is limited to the size of the main memory, the size of the page table cannot exceed the size of the main memory.

Reducing memory overhead of a page table in a dynamic logical partitioning environment

The present invention provides a method and apparatus for providing fragmentation at a transport level along a transmission path. The method comprises receiving a data packet from a first remote device for transmission to a second remote device, wherein the data packet includes a transport-level protocol packet encapsulated in a network-level protocol packet and determining if a size of the received data packet is greater than a maximum transmission unit (MTU) value. The method further comprises performing fragmentation of the data packet at a transport-level protocol into two or more fragments in response to determining that the size of the received data packet is greater than the MTU value and transmitting one or more of the fragments to the second remote device.

Method and apparatus for providing fragmentation at a transport level along a transmission path

A system and method for tuning TCP/IP acknowledgments is provided. The system and method reduces the number of acknowledgments sent by a TCP/IP receiver by determining whether the connection state with the sender warrants using minimal acknowledgments. If minimal acknowledgments are used, the receiver sends fewer acknowledgments to the sender in response to received packets. The number of packets that are received before an acknowledgment is returned is increased until the delay value reaches a threshold value. The threshold value can be determined based on the size of the buffer setup to receive packets from the sender during the session. If errors, such as TCP/IP timeouts or duplicate packets, are detected, the threshold is changed to the last delay value that did not cause errors. If further errors are detected, the system is programmed to revert to sending traditional acknowledgments for the session.

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Round Rock, TX, United States of America

Kiet Hien Lam