mem-cache: fix sendEvent schedule time bugs.

[zephyrols]

The "sendEvent" has been wrongly set as "If it is scheduled and has not been executed yet, it cannot be rescheduled." This results in the inability to update the sendEvent time in a timely manner when more urgent events need to be scheduled.

we put a panic here to check. For test we try checkpoint "/nfs/home/share/jiaxiaoyu/simpoint_checkpoint_zstd_format/spec06_rv64gcb_O3_20m_gcc12.2.0-intFpcOff-jeMalloc/astar_biglakes/562/562_0.202736.zstd", and panic happend.

the breakpoint environment

this is a early prefetch should be shedule before it.

Change-Id: Id8f470ee02ad111fc6b9f90908dc47835b2be38d

[XiangShanRobot]

[Generated by GEM5 Performance Robot]
commit: 2328247
workflow: gem5 Performance Test

Standard Performance

Overall Score

	PR	Master	Diff(%)
Score	16.17	16.17	+0.02 🟢

[XiangShanRobot]

[Generated by GEM5 Performance Robot]
commit: 2328247
workflow: gem5 Ideal BTB Performance Test

Ideal BTB Performance

Overall Score

	PR	Master	Diff(%)
Score	19.78	19.49	+1.44 🟢

[XiangShanRobot]

[Generated by GEM5 Performance Robot]
commit: 2328247
workflow: gem5 Simple RVV Performance Test (Ideal BTB)

Ideal BTB Performance

Overall Score

	PR	Master	Diff(%)
Score	19.51	19.13	+2.01 🟢

[Copilot]

Pull Request Overview

This PR fixes scheduling bugs in the memory cache's sendEvent mechanism. The changes address issues where sendEvent scheduling logic was incorrectly checking for already-scheduled events and add assertions to validate state consistency.

• Removes the early return when sendEvent is already scheduled in PacketQueue::schedSendEvent
• Adds assertion to ensure sendEvent is not scheduled when waiting on retry
• Removes hasSchedSendEvent() check in cache allocation logic to always schedule sends when needed

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/mem/packet_queue.cc	Comments out sendEvent.scheduled() check and adds assertion for retry state validation
src/mem/cache/base.hh	Removes hasSchedSendEvent() condition to unconditionally schedule sends when sched_send is true

[Copilot]

Consider removing commented-out code instead of leaving it in the codebase. If this logic might be needed for reference, document the reasoning in a commit message or code comment explaining why this check was removed.

Suggested change

	// if (sendEvent.scheduled()) {
	// DPRINTF(PacketQueue, "Not scheduling send as already scheduled\n");
	// return;
	// }
	// Removed commented-out code to improve clarity and maintainability.

[XiangShanRobot]

[Generated by GEM5 Performance Robot]
commit: eab8170
workflow: gem5 Performance Test

Standard Performance

Overall Score

	PR	Previous Commit	Diff(%)
Score	16.14	16.17	-0.22 🔴

[XiangShanRobot]

[Generated by GEM5 Performance Robot]
commit: eab8170
workflow: gem5 Ideal BTB Performance Test

Ideal BTB Performance

Overall Score

	PR	Master	Diff(%)
Score	20.00	19.99	+0.08 🟢

[Generated by GEM5 Performance Robot]
commit: eab8170
workflow: gem5 Ideal BTB Performance Test

Ideal BTB Performance

Overall Score

	PR	Previous Commit	Diff(%)
Score	20.00	19.78	+1.15 🟢

[XiangShanRobot]

[Generated by GEM5 Performance Robot]
commit: eab8170
workflow: gem5 Simple RVV Performance Test (Ideal BTB)

Ideal BTB Performance

Overall Score

	PR	Master	Diff(%)
Score	22.35	22.38	-0.16 🔴

[Generated by GEM5 Performance Robot]
commit: eab8170
workflow: gem5 Simple RVV Performance Test (Ideal BTB)

Ideal BTB Performance

Overall Score

	PR	Previous Commit	Diff(%)
Score	22.35	19.51	+14.54 🟢