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Annotation of driverkit/notes/DiskStats, revision 1.1

1.1     ! root        1:                        Disk Statistics notes
        !             2:                        
        !             3: int    dk_ndrive = DK_NDRIVE;
        !             4: int    dk_busy;
        !             5: long   dk_time[DK_NDRIVE];
        !             6: long   dk_seek[DK_NDRIVE];
        !             7: long   dk_xfer[DK_NDRIVE];
        !             8: long   dk_wds[DK_NDRIVE];
        !             9: float  dk_mspw[DK_NDRIVE];             // never Used!!!!!!
        !            10: long   dk_bps[DK_NDRIVE];
        !            11: 
        !            12: SCSI Disk Driver
        !            13: 
        !            14:        dk_bps[dk] set once, in sdsetbratio. Calculated from values in 
        !            15:                label (dlp->nsect, dlp->dl_secsize, dlp->rpm)
        !            16:        sdstart:
        !            17:                dk_busy |= 1 << device;
        !            18:                dk_xfer[device]++;
        !            19:                dk_seek[device]++;
        !            20:                dk_wds[device] += bp->b_bcount >> 6;
        !            21:                
        !            22:        sdintr:
        !            23:                dk_busy &=~ (1 << device);
        !            24:                
        !            25: OD driver
        !            26: 
        !            27:        od_read_label:
        !            28:                dk_bps[dk] = l->dl_secsize * l->dl_nsect *
        !            29:                                l->dl_rpm / 60;
        !            30: 
        !            31:        od_go:
        !            32:                dk_busy |= 1 << dk;
        !            33:                dk_xfer[dk]++;
        !            34:                dk_wds[dk] += bp->b_bcount >> 6;
        !            35:        
        !            36:        od_done:
        !            37:                dk_busy &= ~(1 << dk);
        !            38:                
        !            39:        state machine starting seek:
        !            40:                dk_seek[dk]++;
        !            41: 
        !            42: In gatherstats(), every hardclock (hz times per second?)
        !            43: 
        !            44:        for (s = 0; s < DK_NDRIVE; s++)
        !            45:                if (dk_busy & (1 << s))
        !            46:                        dk_time[s]++;
        !            47: 
        !            48: In mach table() syscall:
        !            49: 
        !            50:        ti.io_dkbusy = dk_busy;
        !            51:        ti.io_ndrive = dk_ndrive;       // don't know any better
        !            52:        
        !            53: In bsd machine_table() syscall:
        !            54: 
        !            55:        ti.io_dkbusy = dk_busy;
        !            56:        ti.io_ndrive = 0;
        !            57:        for (i = 0; bus_dinit[i].bd_driver; i++)
        !            58:                if (bus_dinit[i].bd_dk >= 0)
        !            59:                        ti.io_ndrive++;
        !            60: 
        !            61: Proposed IODiskDevice counters (all unsigned int's)
        !            62:        readOps         
        !            63:        bytesRead
        !            64:        timeReading
        !            65:        writeOps
        !            66:        timeWriting
        !            67:        bytesWritten
        !            68:        
        !            69: methods
        !            70:        - (void)startRead;
        !            71:        - (void)endRead : (int)bytesTransferred;
        !            72:        - (void)startWrite;
        !            73:        - (void)endWrite : (int)bytesTransferred;
        !            74: 
        !            75: ..also, in kernel, current dk_XXX variables will be supported for a while.

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