4. EXCEPTIONS › 4.3 Detailed Exception Descriptions › 00316: CPU Degraded by TLB/Cache Buffer Failure(s)

00316: CPU Degraded by TLB/Cache Buffer Failure(s)

FILE              TSO System Activity
SAS FILE NAME     DETAIL.TSOTSO01
SOURCE LOCATION   sharedprefix.MICS.SOURCE(DYTSOEXC)

SEVERITY          Critical      (SEVERITY='C')
MANAGEMENT AREA   Performance   (MGMTAREA='PERFORMANCE')

PURPOSE      Indicates probable severe degradation of CPU
             speed.

RATIONALE    Large processor performance depends on a very
             high percentage of memory fetches being
             satisfied from the CPU's ultra-high-speed
             "cache" buffer and an even higher percentage of
             virtual-to-real address translations being
             accomplished from the CPU's Translation Look-
             Aside Buffer (TLB).

             The LOGICAL operation of the system can continue
             without either or both of the cache and the TLB,
             but performance impact would become worse.  For
             this reason, the hardware informs MVS of any
             impact on the TLB or cache via a "degradation"
             "soft" machine check.

             Note that it is possible to lose only part of
             the TLB or cache.  The hardware is segmented on
             most models so it may degrade rather than either
             working perfectly or not at all.

DEFINITION   This exception is noted when the data element
             TSOXTLBX (Intvls When TLB or Cache Machine Chks)
             is found with a nonzero value.  See Appendix B
             for more information on this data element.

EXCEPTION    The SAS statements identifying the exception
STATEMENTS   situation and describing the condition are
             stored in the source member named in SOURCE
             LOCATION and are described below:

************************************************************;
*
** 00316
** CPU DEGRADED BY TLB/CACHE BUFFER FAILURE
*;
IF TSOXTLBX > 0
 THEN DO;
  EXCCODE='00316'; SEVERITY='C'; MGMTAREA='PERFORMANCE';
  EXCDESC1='CPU DEGRADED BY TLB/CACHE BUFFER FAILURE';
  EXCDESC2=' ENDTS=' || PUT(ENDTS,DATETIME19.2);
  LINK HIT;
END;

THRESHOLD    None required.
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