Undocumented L1D cache event

By: Robert Williams (crispysilicon.delete@this.gmail.com), May 6, 2019 8:37 am
Room: Moderated Discussions
Travis Downs (travis.downs.delete@this.gmail.com) on May 1, 2019 4:06 pm wrote:
> Maybe you will find a use for this event one day! Of course, as a undocumented event it
> comes with no warranty, it may damage your CPU or send bolts of lightning out of the USB
> port to fry your cat as punishment for using it, but so far so good for my use cases.
>

My cat walked past my case as I was reading this and I couldn't help but glance at the front ports. Well played sir, well played.

Ice Lake


"CollectPEBSRecord": "2",
+ "PublicDescription": "Counts number of L1D misses that are outstanding in each cycle, that is each cycle the number of Fill Buffers (FB) outstanding required by Demand Reads. FB either is held by demand loads, or it is held by non-demand loads and gets hit at least once by demand. The valid outstanding interval is defined until the FB deallocation by one of the following ways: from FB allocation, if FB is allocated by demand from the demand Hit FB, if it is allocated by hardware or software prefetch. Note: In the L1D, a Demand Read contains cacheable or noncacheable demand loads, including ones causing cache-line splits and reads due to page walks resulted from any request type.",
+ "EventCode": "0x48",
+ "Counter": "0,1,2,3",
+ "UMask": "0x1",
+ "PEBScounters": "0,1,2,3",
+ "EventName": "L1D_PEND_MISS.PENDING",
+ "SampleAfterValue": "2000003",
+ "BriefDescription": "Number of L1D misses that are outstanding"
+ },
+ {
+ "CollectPEBSRecord": "2",
+ "PublicDescription": "Counts duration of L1D miss outstanding in cycles.",
+ "EventCode": "0x48",
+ "Counter": "0,1,2,3",
+ "UMask": "0x1",
+ "PEBScounters": "0,1,2,3",
+ "EventName": "L1D_PEND_MISS.PENDING_CYCLES",
+ "SampleAfterValue": "2000003",
+ "BriefDescription": "Cycles with L1D load Misses outstanding.",
+ "CounterMask": "1"
+ },
+ {
+ "CollectPEBSRecord": "2",
+ "PublicDescription": "Counts number of cycles a demand request has waited due to L1D Fill Buffer (FB) unavailablability. Demand requests include cacheable/uncacheable demand load, store, lock or SW prefetch accesses.",
+ "EventCode": "0x48",
+ "Counter": "0,1,2,3",
+ "UMask": "0x2",
+ "PEBScounters": "0,1,2,3",
+ "EventName": "L1D_PEND_MISS.FB_FULL",
+ "SampleAfterValue": "2000003",
+ "BriefDescription": "Number of cycles a demand request has waited due to L1D Fill Buffer (FB) unavailablability."
+ },
+ {
+ "CollectPEBSRecord": "2",
+ "PublicDescription": "Counts number of phases a demand request has waited due to L1D Fill Buffer (FB) unavailablability. Demand requests include cacheable/uncacheable demand load, store, lock or SW prefetch accesses.",
+ "EventCode": "0x48",
+ "Counter": "0,1,2,3",
+ "UMask": "0x2",
+ "PEBScounters": "0,1,2,3",
+ "EventName": "L1D_PEND_MISS.FB_FULL_PERIODS",
+ "SampleAfterValue": "2000003",
+ "BriefDescription": "Number of phases a demand request has waited due to L1D Fill Buffer (FB) unavailablability.",
+ "CounterMask": "1",
+ "EdgeDetect": "1"
+ },
+ {
+ "CollectPEBSRecord": "2",
+ "PublicDescription": "Counts number of cycles a demand request has waited due to L1D due to lack of L2 resources. Demand requests include cacheable/uncacheable demand load, store, lock or SW prefetch accesses.",
+ "EventCode": "0x48",
+ "Counter": "0,1,2,3",
+ "UMask": "0x4",
+ "PEBScounters": "0,1,2,3",
+ "EventName": "L1D_PEND_MISS.L2_STALL",
+ "SampleAfterValue": "2000003",
+ "BriefDescription": "Number of cycles a demand request has waited due to L1D due to lack of L2 resources."

< Previous Post in ThreadNext Post in Thread >
TopicPosted ByDate
Undocumented L1D cache eventTravis Downs2019/05/01 04:06 PM
  Undocumented L1D cache eventGabriele Svelto2019/05/06 12:08 AM
  Undocumented L1D cache eventRobert Williams2019/05/06 08:37 AM
    Undocumented L1D cache eventTravis Downs2019/05/06 12:58 PM
      It does have a useRobert Williams2019/05/16 09:23 AM
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