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Conference perfom::internal_perf_tools

Title:Internal Performance Tools
Moderator:DECCXX::WIBECAN
Created:Mon Jun 21 1993
Last Modified:Thu May 15 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:94
Total number of notes:284

93.0. "How to interpret bcache_miss events withou Bcache ?" by HYDRA::SHEN () Wed Apr 09 1997 19:46

    I ran iprobe (Nt40IprobeT23Ev5) on a dpw433a/without Board level cache
    (miata) wnt v4.0/sp2. iprobe reported a small number (128) of bcache_miss
    events during a 30 second period. How should the data be interpreted ?
    
    Robert
    
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93.1solar flare? cometary visitors?MSBCS::SCHNEIDERSay it with ASCIIThu Apr 10 1997 11:298
    Hi, Robert,
    
    Knowing your sense of humor, I'm not sure if you really want an
    answer, but if so I reckon you'd have to ask the board designers
    what's connected to the associated pins on the Alpha chip.
    
    Cheers,
    Chuck
93.2re. .1HYDRA::SHENThu Apr 10 1997 16:2812
    re. .1
    
    Hi, Chuck,
    
    	Very nice to hear from you.
    
    	I was really not trying to be funny. My ISV partner in Colorado
    definitely would ask me that question as they are keen on making the
    best out of dpw's board level cache for their application.
    
    Robert
    
93.3Its counting FILLsROCK::BANNONTue Apr 29 1997 13:4212
    Heres the code from the EV5 model:
    /*
     * Each fill idicates that a miss was generated and seviced by memory
     */
    c_bsq->pm_bc_miss_a_h = EXTW(c_bsq_dtb->bsq_state_10b_h, C_BSQ__FILL);
    
    The counter counts fills because there are cases where the a read
    that misses will be restarted.  We didn't want to count these cases,
    so we counted the number of fills.
    Pete
    
    
93.4re. .3HYDRA::SHENThu May 01 1997 18:3127
    Hi, Pete,
    
    	Thanks for your reply of .3.
    
    	Does it mean that, on a machine without board level cache, the
    dcache_miss rate is the same as bcache_miss rate and iprobe simply
    reported
    so ? If it is the case, then I have peace of mind and my curiosity is
    cured.
    
    	I would like to report a somewhat different, though related problem
    with iprobe "Nt40IprobeT23Ev5"
               (MD5 hash value: d0 52 bd da 60 ba c8 6f 23 d4 3f 0b cd 58
    c9 7b)
    
    	the following iprobe command would crash the system and give you a
    blue screen STOP:0x0000001E on WNT4.0/ALPHA:
    
    C:> iprobe -method sample -duration 30 dcache_access bcache_miss
    	
    	Please take a look to see if you can reproduce it on other
    WNT/Alpha
    varieties. Thanks
    
    Robert