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timing(MainPipe): fix critical path from Dir error to GrantBuffer#448

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linjuanZ merged 1 commit intomasterfrom
timing-dir-2-grantbuffer
Dec 1, 2025
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timing(MainPipe): fix critical path from Dir error to GrantBuffer#448
linjuanZ merged 1 commit intomasterfrom
timing-dir-2-grantbuffer

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@linjuanZ linjuanZ commented Dec 1, 2025

Consider the following timing path:

The error signal returned by Directory is used by forwarding snoop to determine whether to allocate an MSHR. If there is an error, a SnpResp is returned directly; otherwise, an MSHR needs to be allocated. This signal also affects the opcode sent to GrantBuffer. GrantBuffer uses whether the opcode is HintAck to decide whether to enqueue.

However, the opcode is, either the opcode pre-set by MSHR in MSHR requests, or sink_req_s3.bits.opcode generated in s3. It can be determined simply by using mshr_req_s3 because when valid output to GrantBuffer is false, we do not need an accurate opcode.

@linjuanZ
timing(MainPipe): fix critical path from Dir error to GrantBuffer
bd8ff2b 
Consider the following timing path:

The `error` signal returned by Directory is used by forwarding snoop to
determine whether to allocate an MSHR. If there is an error, a SnpResp
is returned directly; otherwise, an MSHR needs to be allocated. This
signal also affects the opcode sent to GrantBuffer. GrantBuffer uses
whether the opcode is HintAck to decide whether to enqueue.

However, the opcode is, either the opcode pre-set by MSHR in MSHR
requests, or `sink_req_s3.bits.opcode` generated in s3. It can be
determined simply by using `mshr_req_s3` because when `valid` output to
GrantBuffer is false, we do not need an accurate opcode.
@linjuanZ linjuanZ force-pushed the timing-dir-2-grantbuffer branch from 754dd2b to bd8ff2b Compare December 1, 2025 09:05
@linjuanZ linjuanZ marked this pull request as ready for review December 1, 2025 09:22
@linjuanZ linjuanZ merged commit 62195c6 into master Dec 1, 2025
1 check passed
@linjuanZ linjuanZ deleted the timing-dir-2-grantbuffer branch December 1, 2025 09:59
yu-yake2002 added a commit to OpenXiangShan/HBL2 that referenced this pull request Mar 6, 2026
@yu-yake2002
Bump coupledL2 upstream at Mar 5, 2026
30a4cb1 
Merge coupledL2 commits from 95e8de to 727a04c (xs/master),
which is the latest on xs/master as of Mar 5, 2026.

Squashed commit of the following:

commit 62195c6
Author: zhanglinjuan <zhanglinjuan16@mails.ucas.ac.cn>
Date:   Mon Dec 01 17:59:00 2025 +0800

    timing(MainPipe): fix critical path from Dir error to GrantBuffer (OpenXiangShan#448)

commit fffb491
Author: Ding Haonan <kumonda@kucro3.org>
Date:   Thu Dec 04 11:36:48 2025 +0800

    timing(TL2CHICoupledL2): 2-stage cap P-Credit Queue (OpenXiangShan#449)

commit f118bca
Author: Yanqin Li <maxpicca@qq.com>
Date:   Tue Dec 16 21:26:05 2025 +0800

    refactor: refine prefetch statistics in topdown monitor (OpenXiangShan#452)

commit b40da89
Author: Ma-YX <71326427+Ma-YX@users.noreply.github.com>
Date:   Wed Dec 17 18:58:51 2025 +0800

    fix(TXDAT): fix wrong DataCheck generation when data invalid (OpenXiangShan#455)

commit e4fd161
Author: Ma-YX <71326427+Ma-YX@users.noreply.github.com>
Date:   Wed Dec 17 21:36:01 2025 +0800

    fix(CoupledL2): fix l2MissMatch io compilation error (OpenXiangShan#456)

commit 4e4a6aa
Author: Kunlin You <youkunlin20@mails.ucas.ac.cn>
Date:   Thu Dec 18 19:13:20 2025 +0800

    feat(clockGate): support disable ClockGate with parameters (OpenXiangShan#451)

commit feacfb5
Author: zhaohong1988 <156632870+zhaohong1988@users.noreply.github.com>
Date:   Fri Dec 19 00:24:20 2025 +0800

    fix(MMIOBridge): modify TIMERRange from fix value to soc parameter (OpenXiangShan#453)

commit c5ad8f4
Author: Yanqin Li <maxpicca@qq.com>
Date:   Fri Dec 19 00:24:53 2025 +0800

    ci: add submodule check and remove the dependency of utility in OpenLLC (OpenXiangShan#454)

commit ea0c313
Author: Ding Haonan <kumonda@kucro3.org>
Date:   Fri Dec 26 09:41:32 2025 +0800

    fix(MMIOBridge): remove redundant BEU range exclusion in L2 (OpenXiangShan#457)

commit f292774
Author: Ding Haonan <kumonda@kucro3.org>
Date:   Thu Jan 08 10:15:15 2026 +0800

    fix(Opcode): missing SnpPreferUniqueFwd in SnpXFwd (OpenXiangShan#460)

commit 59f3025
Author: Ma-YX <71326427+Ma-YX@users.noreply.github.com>
Date:   Wed Jan 14 15:59:43 2026 +0800

    fix(MainPipe): fix l2Error_s3 generation logic (OpenXiangShan#463)

commit 3c9525f
Author: Haoyuan Feng <fenghaoyuan19@mails.ucas.ac.cn>
Date:   Mon Feb 02 10:17:49 2026 +0800

    fix(ClockGate): fix bug that ICG is invalid when disable mbist (OpenXiangShan#470)

commit 0d20557
Author: yulightenyu <145419941+yulightenyu@users.noreply.github.com>
Date:   Tue Mar 03 14:26:16 2026 +0800

    fix(AsyncBridge): restore performance considering async depth is 4 (OpenXiangShan#472)

commit ef2deb5
Author: Ding Haonan <kumonda@kucro3.org>
Date:   Wed Mar 04 16:20:19 2026 +0800

    fix(MSHR): hold LikelyShared on retried writes (OpenXiangShan#474)

commit 727a04c
Author: Haoyuan Feng <fenghaoyuan19@mails.ucas.ac.cn>
Date:   Wed Mar 04 17:01:33 2026 +0800

    feat(mmioBridge): increase mmioBridgeSize to 16 for better NC perf (OpenXiangShan#475)
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