- 14 7月, 2022 5 次提交
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由 Yinan Xu 提交于
* rob: separate walk and commit valid bits * rob: optimize instrCnt timing * rob: fix blockCommit condition when flushPipe When flushPipe is enabled, it will block commits in ROB. However, in the deqPtrModule, the commit is not blocked. This commit fixes the issue.
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由 Lemover 提交于
Old Edition: 2 ld tlb but with same entries. 2 st tlb but wih the same entries. The 'duplicate' is used for timing optimization that each tlb can be placed close to mem access pipeline unit. Problem: The duplicate tlb takes more Power/Area. New Edition: Only 1 ld tlb and 1 st tlb now. If the area is not ok, may merge ld and st together. Fix: fix some syntax bug when changing parameters
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由 Yinan Xu 提交于
Balance between the first numDeq ports. Possible IPC increase?
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由 Lemover 提交于
* l1tlb: l1tlb entry uses one-hot size * l1tlb: fix victim write when level usage changes
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由 Yinan Xu 提交于
* ibuf: optimize register namings * ibuffer: re-write data read logic
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- 13 7月, 2022 2 次提交
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由 Yinan Xu 提交于
* dpq: add slow path for non-critical registers This commit separates the data module in Dispatch to slow and fast path. Slow path stores the data with a bad timing at Dispatch but a good timing at Dispatch2. Thus should benefit the timing at Dispatch, such as the LFST. For now, we merge the slow and fast data module. Chisel DCE does not eliminate the dead registers. We manully merge the two data modules for now. * dpq: optimize timing for enqPtr/deqPtr matching This commit optimizes the matching timing between enqPtr and deqPtr, which is used further for bypassing enqData to deqData. Now enqOffset and deqPtr/enqPtr matching work in parallel.
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由 Yinan Xu 提交于
This commit moves the decoder of software prefetch instructions to the rename stage. Previously the decoding of software prefetch instructions affects the imm gen and causes a long critical path.
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- 12 7月, 2022 6 次提交
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由 William Wang 提交于
This commit adds an extra cycle for load pipeline. It should fix timing problem caused by load pipeline. Huge perf loss is expected. Now load data result is sent to rs in load_s3, load may hit hint (fastUop.valid) is sent to rs in load_s2. We add a 3 cycle load to load fast forward data path. There should be enough time to forward data inside memory block. We will refactor code and add a load_s3 module in the future. BREAKING CHANGE: load pipeline reorginized
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由 Yinan Xu 提交于
* rat: map all arch registers to zero when init * freelist: fix stepBack width * freelist: fix timing of free offset
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由 zhanglinjuan 提交于
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由 Yinan Xu 提交于
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由 Yinan Xu 提交于
* ctrl: copy dispatch2 to avoid cross-module loops This commit makes copies of dispatch2 in CtrlBlock to avoid long cross-module timing loop paths. Should be good for timing. * dpq: re-write queue read logic This commit adds a Reg-Vec to store the queue read data. Since most queues read at most the current numRead and the next numRead entries, the read timing can be optimized by reading the data one cycle earlier.
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由 Yinan Xu 提交于
This commit optimizes the timing of reservation stations. * dispatched uops are latched and bypassed to s1_out * wakeup from slowPorts are latched and bypassed to s1_data * rs: optimize allocation selection Change select policy for allocation. Should avoid issuing the just dispatched instructions in some cases. * rs: disable load balance for load units
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- 11 7月, 2022 1 次提交
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由 Yinan Xu 提交于
This commit fixes the bug that instructions with exceptions may trigger instruction fusion if the previous instruction at the same position is fused. When the input instruction pair is invalid, the fusion decoder should always set out.valid to false.B at the next cycle. The bug is caused by the RegEnable for instrPairValid, which should be updated at every clock cycle. Should fix the error introduced by 0febc381 and the regression failure at https://github.com/OpenXiangShan/XiangShan/actions/runs/2645135867.
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- 10 7月, 2022 1 次提交
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由 Yinan Xu 提交于
This commit adds separated redirect registers in ExuBlock and MemBlock. They have one cycle latency compared to redirect in CtrlBlock. This will help reduce the fanout of redirect registers.
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- 09 7月, 2022 2 次提交
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由 Yinan Xu 提交于
This commit moves the fusion decoder to both decode and rename stage. In the decode stage, fusion decoder determines whether the instruction pairs can be fused. Valid bits of decode are not affected by fusion decoder. This should fix the timing issues of rename.valid. In the rename stage, some fields are updated according the result of fusion decoder. This will bring a minor timing path to both valid and other fields in uop in the rename stage. However, since freelist and rat have worse timing. This should not cause timing issues.
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由 Lemover 提交于
* dtlb: replace sram to SyncDataModule, nWays is useless * itlb: if miss_sameCycle, regnext ptw resp and block tlb check * dtlb: for normal_entry, when refill, do not need set miss by force
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- 08 7月, 2022 2 次提交
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由 zhanglinjuan 提交于
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由 zhanglinjuan 提交于
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- 07 7月, 2022 1 次提交
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由 Yinan Xu 提交于
This commit fixes the bug that the lsrc(0) of trap instructions is overrided with $a0, which causes timing issues as well.
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- 06 7月, 2022 4 次提交
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由 huxuan0307 提交于
* Remove unused field isRVF * Replace 3rd srcType of non-fp insts and FuType.{fmisc, i2f} insts with SrcType.X
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由 Yinan Xu 提交于
Some modules rely on the walk valid bits of ROB. This commit optimizes the timing by providing separated walk valid bits, which is far better than the commit valid bits.
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由 Yinan Xu 提交于
This commit changes the data modules in Dispatch Queue. We use one-hot indices to read and write the data array.
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由 Yinan Xu 提交于
Optimize the naive implementation of performance counters in decode.
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- 30 6月, 2022 1 次提交
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由 Lingrui98 提交于
* add one cycle stall to ftb miss update, and * add one cycle delay to all other predictors
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- 29 6月, 2022 2 次提交
- 28 6月, 2022 1 次提交
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由 William Wang 提交于
This commit re-pipelines ECC check logic in data cache and exception generate logic for better timing. Now ecc error is checked 1 cycle after reading result from data sram. An extra cycle is added for load writeback to ROB. Future work: move the pipeline to https://github.com/OpenXiangShan/XiangShan/blob/master/src/main/scala/xiangshan/backend/CtrlBlock.scala#L266-L277, which add a regnext. * dcache: repipeline ecc check logic for timing * chore: fix normal loadAccessFault logic * wbu: delay load unit wb for 1 cycle * dcache: add 1 extra cycle for beu error report
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- 27 6月, 2022 3 次提交
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由 Yinan Xu 提交于
* dp2: add a pipeline for load/store Load/store Dispatch2 has a bad timing because it requires the fuType to disguish the out ports. This brings timing issues because the instruction has to read busyTable after the port arbitration. This commit adds a pipeline in dp2Ls, which may cause performance degradation. Instructions are dispatched according to out, and at the next cycle it will leave dp2. * bump difftest trying to fix vcs
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由 William Wang 提交于
* dcache: do not access plru when refill Now we have accessed plru when load miss, we should not access plru when refill * dcache: not not access plru when miss queue full It will help avoid invalid plru access when miss queue full
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由 zhanglinjuan 提交于
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- 26 6月, 2022 1 次提交
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由 Lemover 提交于
fix some bugs. 1. fix l2tlb dead-lock bug l2tlb won't merge requests at same addr. It will be blocked when having too many requests. PtwFilter has a bug that will send too many requests. Add a counter to avoid that. 2. fix sfence sync at mmu different modules in mmu may get sfence at different latency, which will lost requests or some requests have no receiver. Sync the sfence latency manually to avoid the bug. * mmu.filter: add counter not to send to many req to l2tlb * mmu.filter: fix bug that forget counter signal when block issue and deq * mmu: set sfence/csr delay to 2 cycle, must sync in mmu
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- 25 6月, 2022 3 次提交
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由 Lemover 提交于
now the l2tlb page cache are divided into: 1. stageReq: input && read sram valid && will block when sram write 2. stageDelay: get sram data and delay one cycle 3. stageCheck: check hit and ecc result 4. stageResp: output
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由 Lemover 提交于
Background: dtlb has 128 entries stored in sram. 128 sets, 1 ways. advantage: large volume & 1 ways means no tag match logic at data select path disadvantage: 128 sets means long latency at valid select, which is a Vec-Register. Optimization: divide valid select into two-cycles
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由 Yinan Xu 提交于
This commit optimizes the timing of freelist by changing the updating function of headPtr and tailPtr. We maintains an one-hot representation of headPtr and further uses it to read the free registers from the list, which should be better than the previous implementation where headPtr is used to indexed into the queue. The update of tailPtr and the freelist is delayed by one cycle to optimize the timing. Because freelist allocates new registers in the next cycle iff there are more than RenameWidth free registers in this cycle. The freed registers in this cycle will never be used in the next cycle. Thus, we can delay the updating of queue data to the next cycle. We also move the update of tailPtr to the next cycle, since PopCount takes a long timing and we move the last adder to the next cycle. Now the adder works parallely with PopCount. That is, the updating of tailPtr is pipelined.
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- 22 6月, 2022 1 次提交
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由 Yinan Xu 提交于
This commit adds a buffer after the function unit that operate across the integer block and the floating-point block, such as f2i and i2f. For example, previously the out.ready of f2i depends on whether mul/div/csr/jump has a valid instruction out, since f2i has lower priority than them. This ready back-propagates from the integer function units to the floating-point function units, and finally to the floating-point reservation stations (since f2i is fully pipelined). We add a buffer after the function unit to break this ready back-propagation. It incurs one more cycle of execution latency, but we leave it not-fully-optimized for now. Timing can be further optimized if we separates the int writeback and fp writeback in function units. In the current version, the ready of f2i affects the ready of f2f pipelines, which is unnecessary. This is the future work.
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- 21 6月, 2022 1 次提交
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由 Yinan Xu 提交于
This commit adds some registers for performance counters to optimize the timing. Pipelines are added.
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- 20 6月, 2022 2 次提交
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由 Yinan Xu 提交于
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由 William Wang 提交于
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- 18 6月, 2022 1 次提交
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由 Yinan Xu 提交于
This commit changes the lsrc/psrc of LUI in dispatch instead of decode to optimize the timing of lsrc in DecodeStage, which is critical for rename table. lsrc/ldest should be directly get from instr for the timing. Fused instructions change lsrc/ldest now, which will be optimized later.
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