Branch lookahead prefetch for microprocessors
    1.
    发明授权
    Branch lookahead prefetch for microprocessors 有权
    用于微处理器的分支前瞻预取

    公开(公告)号:US07877580B2

    公开(公告)日:2011-01-25

    申请号:US11953799

    申请日:2007-12-10

    IPC分类号: G06F9/00

    CPC分类号: G06F9/3842 G06F9/3861

    摘要: A method of handling program instructions in a microprocessor which reduces delays associated with mispredicted branch instructions, by detecting the occurrence of a stall condition during execution of the program instructions, speculatively executing one or more pending instructions which include at least one branch instruction during the stall condition, and determining the validity of data utilized by the speculative execution. Dispatch logic determines the validity of the data by marking one or more registers of an instruction dispatch unit to indicate which results of the pending instructions are invalid. The speculative execution of instructions can occur across multiple pipeline stages of the microprocessor, and the validity of the data is tracked during their execution in the multiple pipeline stages while monitoring a dependency of the speculatively executed instructions relative to one another during their execution in the multiple pipeline stages.

    摘要翻译: 一种处理微处理器中的程序指令的方法,其通过在执行程序指令期间检测到失速状态的发生来减少与错误预测的分支指令相关联的延迟,推测性地执行一个或多个未决指令,其中包括在失速期间包括至少一个分支指令 条件,并确定投机执行使用的数据的有效性。 调度逻辑通过标记指令调度单元的一个或多个寄存器来指示待处理指令的哪些结果无效来确定数据的有效性。 指令的推测执行可以在微处理器的多个流水线阶段发生,并且在多个流水线阶段的执行期间跟踪数据的有效性,同时在多个流水线阶段的执行期间监视推测性执行的指令相对于彼此的依赖性 流水线阶段

    Using a modified value GPR to enhance lookahead prefetch
    2.
    发明授权
    Using a modified value GPR to enhance lookahead prefetch 失效
    使用修改值GPR来增强前瞻预取

    公开(公告)号:US07421567B2

    公开(公告)日:2008-09-02

    申请号:US11016206

    申请日:2004-12-17

    IPC分类号: G06F9/30 G06F9/40 G06F15/00

    摘要: The present invention allows a microprocessor to identify and speculatively execute future instructions during a stall condition. This allows forward progress to be made through the instruction stream during the stall condition which would otherwise cause the microprocessor or thread of execution to be idle. The execution of such future instructions can initiate a prefetch of data or instructions from a distant cache or main memory, or otherwise make forward progress through the instruction stream. In this manner, when the instructions are re-executed (non speculatively executed) after the stall condition expires, they will execute with a reduced execution latency; e.g. by accessing data prefetched into the L1 cache, or enroute to the processor, or by executing the target instructions following a speculatively resolved mispredicted branch. In speculative mode, instruction operands may be invalid due to source loads that miss the L1 cache, facilities not available in speculative execution mode, or due to speculative instruction results that are not available. Dependency and dirty (i.e. invalid result) bits are tracked and used to determine which speculative instructions are valid for execution. A modified value register storage and bit vector are used to improve the availability of speculative results that would otherwise be discarded once they leave the execution pipeline because they cannot be written to the architected registers. The modified general purpose registers are used to store speculative results when the corresponding instruction reaches writeback and the modified bit vector tracks the results that have been stored there. Younger speculative instructions that do not bypass directly from older instructions will then use this modified data when the corresponding bit in the modified bit vector indicates the data has been modified. Otherwise, data from the architected registers will be used.

    摘要翻译: 本发明允许微处理器在失速状态期间识别和推测地执行未来的指令。 这允许在停顿条件期间通过指令流进行正向进展,否则将导致微处理器或执行线程空闲。 这样的未来指令的执行可以启动来自远程高速缓存或主存储器的数据或指令的预取,或以其他方式通过指令流进行进展。 以这种方式,当在停止条件到期之后重新执行(不推测地执行)指令时,它们将以降低的执行延迟执行; 例如 通过访问预取到L1高速缓存中的数据,或者进入处理器,或通过在推测性地解决的误预测分支之后执行目标指令。 在推测模式中,由于缺少L1缓存的源加载,在推测执行模式下不可用的设备,或由于不可用的推测指令结果,指令操作数可能无效。 跟踪依赖关系和脏(即无效结果)位,并用于确定哪些推测指令对执行有效。 改进的值寄存器存储和位向量被用于提高推测结果的可用性,否则,由于不能将其写入到架构化的寄存器,否则将抛弃执行流水线。 修改后的通用寄存器用于在对应指令到达回写时存储推测结果,修改后的位向量跟踪存储在其中的结果。 当修改的位向量中的相应位指示数据已被修改时,不直接从旧指令旁路的较小的推测指令将使用该修改的数据。 否则,将使用来自架构化寄存器的数据。

    Load lookahead prefetch for microprocessors
    3.
    发明授权
    Load lookahead prefetch for microprocessors 有权
    加载微处理器的前瞻预取

    公开(公告)号:US07594096B2

    公开(公告)日:2009-09-22

    申请号:US11950495

    申请日:2007-12-05

    IPC分类号: G06F9/30 G06F9/40 G06F15/00

    摘要: The present invention allows a microprocessor to identify and speculatively execute future load instructions during a stall condition. This allows forward progress to be made through the instruction stream during the stall condition which would otherwise cause the microprocessor or thread of execution to be idle. The data for such future load instructions can be prefetched from a distant cache or main memory such that when the load instruction is re-executed (non speculative executed) after the stall condition expires, its data will reside either in the L1 cache, or will be enroute to the processor, resulting in a reduced execution latency. When an extended stall condition is detected, load lookahead prefetch is started allowing speculative execution of instructions that would normally have been stalled. In this speculative mode, instruction operands may be invalid due to source loads that miss the L1 cache, facilities not available in speculative execution mode, or due to speculative instruction results that are not available via forwarding and are not written to the architected registers. A set of status bits are used to dynamically keep track of the dependencies between instructions in the pipeline and a bit vector tracks invalid architected facilities with respect to the speculative instruction stream. Both sources of information are used to identify load instructions with valid operands for calculating the load address. If the operands are valid, then a load prefetch operation is started to retrieve data from the cache ahead of time such that it can be available for the load instruction when it is non-speculatively executed.

    摘要翻译: 本发明允许微处理器在失速状态期间识别并推测性地执行未来的加载指令。 这允许在停顿条件期间通过指令流进行正向进展,否则将导致微处理器或执行线程空闲。 可以从远程高速缓存或主存储器预取这样的未来加载指令的数据,使得当停止条件到期之后,当加载指令被重新执行(不推测执行)时,其数据将驻留在L1高速缓存中,或者将 进入处理器,导致执行时间缩短。 当检测到扩展失速条件时,启动加载前瞻预取,允许推测执行通常已经停止的指令。 在这种推测模式中,由于缺少L1高速缓存的源负载,设备在推测执行模式下不可用的设备,或由于不能通过转发而不能使用并且未写入到架构化寄存器的推测性指令结果,指令操作数可能无效。 一组状态位用于动态地跟踪流水线中的指令之间的依赖关系,并且位向量相对于推测性指令流跟踪无效的架构设施。 两个信息来源用于识别加载指令,其中包含用于计算加载地址的有效操作数。 如果操作数有效,则启动加载预取操作以提前从高速缓存中检索数据,使得当非推测性地执行加载指令时,可以对加载指令可用。

    Load lookahead prefetch for microprocessors
    4.
    发明授权
    Load lookahead prefetch for microprocessors 失效
    加载微处理器的前瞻预取

    公开(公告)号:US07444498B2

    公开(公告)日:2008-10-28

    申请号:US11016236

    申请日:2004-12-17

    摘要: The present invention allows a microprocessor to identify and speculatively execute future load instructions during a stall condition. This allows forward progress to be made through the instruction stream during the stall condition which would otherwise cause the microprocessor or thread of execution to be idle. The data for such future load instructions can be prefetched from a distant cache or main memory such that when the load instruction is re-executed (non speculative executed) after the stall condition expires, its data will reside either in the L1 cache, or will be enroute to the processor, resulting in a reduced execution latency. When an extended stall condition is detected, load lookahead prefetch is started allowing speculative execution of instructions that would normally have been stalled. In this speculative mode, instruction operands may be invalid due to source loads that miss the L1 cache, facilities not available in speculative execution mode, or due to speculative instruction results that are not available via forwarding and are not written to the architected registers. A set of status bits are used to dynamically keep track of the dependencies between instructions in the pipeline and a bit vector tracks invalid architected facilities with respect to the speculative instruction stream. Both sources of information are used to identify load instructions with valid operands for calculating the load address. If the operands are valid, then a load prefetch operation is started to retrieve data from the cache ahead of time such that it can be available for the load instruction when it is non-speculatively executed.

    摘要翻译: 本发明允许微处理器在失速状态期间识别并推测性地执行未来的加载指令。 这允许在停顿条件期间通过指令流进行正向进展,否则将导致微处理器或执行线程空闲。 可以从远程高速缓存或主存储器预取这样的未来加载指令的数据,使得当停止条件到期之后,当加载指令被重新执行(不推测执行)时,其数据将驻留在L1高速缓存中,或者将 进入处理器,导致执行时间缩短。 当检测到扩展失速条件时,启动加载前瞻预取,允许推测执行通常已经停止的指令。 在这种推测模式中,由于缺少L1高速缓存的源负载,设备在推测执行模式下不可用的设备,或由于不能通过转发而不能使用并且未写入到架构化寄存器的推测性指令结果,指令操作数可能无效。 一组状态位用于动态地跟踪流水线中的指令之间的依赖关系,并且位向量相对于推测性指令流跟踪无效的架构设施。 两个信息来源用于识别加载指令,其中包含用于计算加载地址的有效操作数。 如果操作数有效,则启动加载预取操作以提前从高速缓存中检索数据,使得当非推测性地执行加载指令时,可以对加载指令可用。

    Using a Modified Value GPR to Enhance Lookahead Prefetch
    5.
    发明申请
    Using a Modified Value GPR to Enhance Lookahead Prefetch 失效
    使用修改值GPR来增强前瞻预取

    公开(公告)号:US20080250230A1

    公开(公告)日:2008-10-09

    申请号:US12061290

    申请日:2008-04-02

    IPC分类号: G06F9/30

    摘要: The present invention allows a microprocessor to identify and speculatively execute future instructions during a stall condition. This allows forward progress to be made through the instruction stream during the stall condition which would otherwise cause the microprocessor or thread of execution to be idle. The execution of such future instructions can initiate a prefetch of data or instructions from a distant cache or main memory, or otherwise make forward progress through the instruction stream. In this manner, when the instructions are re-executed (non speculatively executed) after the stall condition expires, they will execute with a reduced execution latency; e.g. by accessing data prefetched into the L1 cache, or enroute to the processor, or by executing the target instructions following a speculatively resolved mispredicted branch. In speculative mode, instruction operands may be invalid due to source loads that miss the L1 cache, facilities not available in speculative execution mode, or due to speculative instruction results that are not available. Dependency and dirty (i.e. invalid result) bits are tracked and used to determine which speculative instructions are valid for execution. A modified value register storage and bit vector are used to improve the availability of speculative results that would otherwise be discarded once they leave the execution pipeline because they cannot be written to the architected registers. The modified general purpose registers are used to store speculative results when the corresponding instruction reaches writeback and the modified bit vector tracks the results that have been stored there. Younger speculative instructions that do not bypass directly from older instructions will then use this modified data when the corresponding bit in the modified bit vector indicates the data has been modified. Otherwise, data from the architected registers will be used.

    摘要翻译: 本发明允许微处理器在失速状态期间识别和推测地执行未来的指令。 这允许在停顿条件期间通过指令流进行正向进展,否则将导致微处理器或执行线程空闲。 这样的未来指令的执行可以启动来自远程高速缓存或主存储器的数据或指令的预取,或以其他方式通过指令流进行进展。 以这种方式,当在停止条件到期之后重新执行(不推测地执行)指令时,它们将以降低的执行延迟执行; 例如 通过访问预取到L1高速缓存中的数据,或者进入处理器,或通过在推测性地解决的误预测分支之后执行目标指令。 在推测模式中,由于缺少L1缓存的源加载,在推测执行模式下不可用的设备,或由于不可用的推测指令结果,指令操作数可能无效。 跟踪依赖关系和脏(即无效结果)位,并用于确定哪些推测指令对执行有效。 改进的值寄存器存储和位向量被用于提高推测结果的可用性,否则,由于不能将其写入到架构化的寄存器,否则将抛弃执行流水线。 修改后的通用寄存器用于在对应指令到达回写时存储推测结果,修改后的位向量跟踪存储在其中的结果。 当修改的位向量中的相应位指示数据已被修改时,不直接从旧指令旁路的较小的推测指令将使用该修改的数据。 否则,将使用来自架构化寄存器的数据。

    Using a modified value GPR to enhance lookahead prefetch
    6.
    发明授权
    Using a modified value GPR to enhance lookahead prefetch 失效
    使用修改值GPR来增强前瞻预取

    公开(公告)号:US07620799B2

    公开(公告)日:2009-11-17

    申请号:US12061290

    申请日:2008-04-02

    IPC分类号: G06F9/30 G06F9/40 G06F15/00

    摘要: Mechanisms to identify and speculatively execute future instructions during a stall condition are provided. In speculative mode, instruction operands may be invalid due to a number of reasons. Dependency and dirty bits are tracked and used to determine which speculative instructions are valid for execution. A modified value register storage and bit vector are used to improve the availability of speculative results that would otherwise be discarded once they leave the execution pipeline because they cannot be written to the architected registers. The modified general purpose registers are used to store speculative results when the corresponding instruction reaches writeback and the modified bit vector tracks the results that have been stored there. Younger speculative instructions that do not bypass directly from older instructions use this modified data when the corresponding bit in the modified bit vector indicates the data has been modified. Otherwise, data from the architected registers is used.

    摘要翻译: 提供了在失速状态下识别和推测执行未来指令的机制。 在推测模式下,指令操作数可能因无数原因而无效。 跟踪依赖关系和脏位,并用于确定哪些推测指令对执行有效。 改进的值寄存器存储和位向量被用于提高推测结果的可用性,否则,由于不能将其写入到架构化的寄存器,否则将抛弃执行流水线。 修改后的通用寄存器用于在对应指令到达回写时存储推测结果,修改后的位向量跟踪存储在其中的结果。 当修改的位向量中的相应位指示数据已被修改时,不直接从旧指令中绕过的较小的推测指令使用该修改的数据。 否则,将使用来自架构寄存器的数据。

    Branch lookahead prefetch for microprocessors
    7.
    发明授权
    Branch lookahead prefetch for microprocessors 失效
    用于微处理器的分支前瞻预取

    公开(公告)号:US07552318B2

    公开(公告)日:2009-06-23

    申请号:US11016200

    申请日:2004-12-17

    IPC分类号: G06F9/00

    CPC分类号: G06F9/3842 G06F9/3861

    摘要: A method of handling program instructions in a microprocessor which reduces delays associated with mispredicted branch instructions, by detecting the occurrence of a stall condition during execution of the program instructions, speculatively executing one or more pending instructions which include at least one branch instruction during the stall condition, and determining the validity of data utilized by the speculative execution. Dispatch logic determines the validity of the data by marking one or more registers of an instruction dispatch unit to indicate which results of the pending instructions are invalid. The speculative execution of instructions can occur across multiple pipeline stages of the microprocessor, and the validity of the data is tracked during their execution in the multiple pipeline stages while monitoring a dependency of the speculatively executed instructions relative to one another during their execution in the multiple pipeline stages.

    摘要翻译: 一种处理微处理器中的程序指令的方法,其通过在执行程序指令期间检测到失速状态的发生来减少与错误预测的分支指令相关联的延迟,推测性地执行一个或多个未决指令,其中包括在失速期间包括至少一个分支指令 条件,并确定投机执行使用的数据的有效性。 调度逻辑通过标记指令调度单元的一个或多个寄存器来指示待处理指令的哪些结果无效来确定数据的有效性。 指令的推测执行可以在微处理器的多个流水线阶段发生,并且在多个流水线阶段的执行期间跟踪数据的有效性,同时在多个流水线阶段的执行期间监视推测性执行的指令相对于彼此的依赖性 流水线阶段

    Instruction tracking system for processors
    8.
    发明授权
    Instruction tracking system for processors 失效
    处理器指令跟踪系统

    公开(公告)号:US08521998B2

    公开(公告)日:2013-08-27

    申请号:US12793718

    申请日:2010-06-04

    IPC分类号: G06F9/30

    摘要: A method and apparatus for tracking instructions in a processor. A completion unit in the processor receives an instruction group to add to a table to form a received instruction group. In response to receiving the received instruction group, the completion unit determines whether an entry is present that contains a previously stored instruction group in a first location and has space for storing the received instruction group. In response to the entry being present, the completion unit stores the received instruction group in a second location in the entry to form a stored instruction group.

    摘要翻译: 一种用于跟踪处理器中的指令的方法和装置。 处理器中的完成单元接收到添加到表中以形成接收到的指令组的指令组。 响应于接收到接收到的指令组,完成单元确定是否存在包含在第一位置中的先前存储的指令组的条目,并且具有用于存储接收到的指令组的空间。 响应于存在的条目,完成单元将接收到的指令组存储在条目中的第二位置,以形成存储的指令组。

    Thread priority method for ensuring processing fairness in simultaneous multi-threading microprocessors
    9.
    发明授权
    Thread priority method for ensuring processing fairness in simultaneous multi-threading microprocessors 失效
    线程优先级方法,用于确保同时多线程微处理器的处理公平性

    公开(公告)号:US08418180B2

    公开(公告)日:2013-04-09

    申请号:US12129876

    申请日:2008-05-30

    IPC分类号: G06F9/46

    摘要: A method, apparatus, and computer program product are disclosed for ensuring processing fairness in simultaneous multi-threading (SMT) microprocessors. A clock cycle priority is assigned to a first thread and to a second thread during a standard selection state that lasts for an expected number of clock cycles by selecting the first thread to be a primary thread and the second thread to be a secondary thread. If a condition exists that requires overriding, an override state is executed by selecting the second thread to be the primary thread and the first thread to be the secondary thread. The override state is forced to be executed for an override period of time which equals the expected number of clock cycles plus a forced number of clock cycles. The forced number of clock cycles is granted to the first thread in response to the first thread again becoming the primary thread.

    摘要翻译: 公开了一种用于确保同时多线程(SMT)微处理器中的处理公平性的方法,装置和计算机程序产品。 在通过选择作为主线程的第一线程和第二线程成为辅线程的持续期望的时钟周期数的标准选择状态期间,将时钟周期优先级分配给第一线程和第二线程。 如果存在需要覆盖的条件,则通过选择作为主线程的第二个线程和第一个线程作为辅助线程来执行覆盖状态。 超时状态被强制执行超时时间等于预期的时钟周期数加上强制的时钟周期数。 响应于第一个线程再次成为主线程,强制的时钟周期数被授予第一个线程。

    Dynamic recalculation of resource vector at issue queue for steering of dependent instructions
    10.
    发明授权
    Dynamic recalculation of resource vector at issue queue for steering of dependent instructions 有权
    动态重新计算依赖指令转向问题队列中的资源向量

    公开(公告)号:US07650486B2

    公开(公告)日:2010-01-19

    申请号:US12013572

    申请日:2008-01-14

    IPC分类号: G06F9/38

    CPC分类号: G06F9/3851 G06F9/3836

    摘要: A method and apparatus for steering instructions dynamically, at issue time, so as to maximize the efficiency of use of execution units being shared by multiple threads being processed by an SMT processor. Resource vectors are used at issue time to redirect instructions, from threads being processed simultaneously, to shared resources for which the multiple threads are competing. The existing resource vectors for instructions that are queued for issuance are analyzed and, where appropriate, dynamically recalculated and modified for maximum efficiency.

    摘要翻译: 一种用于在问题时刻动态地转向指令的方法和装置,以便最大化由SMT处理器处理的多个线程共享的执行单元的使用效率。 在发布时使用资源向量将来自正在被处理的线程的指令重定向到多个线程正在竞争的共享资源。 分析用于发行排队的指令的现有资源向量,并在适当情况下动态重新计算和修改以最大限度地提高效率。