Utilizing zEDC Hardware Accelerator

Explains how to use the IBM zEDC Hardware Accelerator.
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You can offload compression and decompression operations to the IBM zEDC Hardware Accelerator. zEDC is an optional feature available to the latest z/Architecture processors that provides data compression services at the hardware level. Using zEDC reduces both CPU utilization costs and the elapsed time of data transfers that use the zlib compression algorithm. Data compression and decompression account for a significant portion of CPU utilization for a data transfer. Therefore, when you use zEDC with CA XCOM Data Transport, you can increase computing capacity and lower the cost of compressing data.
CA XCOM Data Transport attempts to offload zlib data compression and decompression operations to zEDC when you meet
all
of the following requirements:
  • Meet Hardware and Software Prerequisites
  • Configure zEDC Minimum Buffer Sizes
  • Use zLIB Compression Algorithm
  • Meet Security Requirements
  • Review zEDC-Related Messages
Meet Hardware and Software Prerequisites
Meet the following hardware and software prerequisites:
  • Install and configure the zEDC hardware on the processor that you use for transferring data with CA XCOM Data Transport. For instructions, see your zEDC documentation.
  • Verify the presence of the zEDC hardware. Use the
    D PCIE
    z/OS console command, as follows:
    D PCIE IQP022I 10.10.58 DISPLAY PCIE 615 PCIE 0011 ACTIVE PFID DEVICE TYPE NAME STATUS ASID JOBNAME CHID VFN 000000F6 Hardware Accelerator ALLC 0012 FPGHWAM 0150 0006
  • Verify that the system is running at a minimum of z/OS 2.1.
  • The zEDC product feature must be enabled to z/OS. To verify the presence of the zEDC feature, use the
    D PROD,REG,FEATURENAME(ZEDC)
    z/OS console command, as follows:
    D PROD,REG,FEATURENAME(ZEDC) IFA111I 11.29.05 PROD DISPLAY 812 S OWNER NAME FEATURE VERSION ID E IBM CORP z/OS ZEDC 02.02.00 5650-ZOS
Configure zEDC Minimum Buffer Sizes
To move the data compression and decompression functions to the zEDC, follow these steps:
  1. Determine and set the buffer sizes.
  2. Set the MAXPACK parameter.
  3. Set the PACK parameter.
Determine and Set the Buffer Sizes
If necessary, consult your z/OS administrator for assistance to perform this step. The size of the data blocks being compressed or decompressed must meet the system-wide configured minimum buffer sizes. This requirement is enforced by the IBM-supplied zEDC-aware version of the zlib data compression algorithm.
To determine minimum buffer sizes, enter the
D IQP
z/OS console command. For example:
D IQP IQP066I 09.59.54 DISPLAY IQP 613 zEDC Information MAXSEGMENTS: 4 (64M) Previous MAXSEGMENTS: N/A Allocated segments: 4 (64M) Used segments: 0 (0M) DEFMINREQSIZE: 4K INFMINREQSIZE: 16K Feature Enablement: Enabled
  • DEFMINREQSIZE
    Specifies the minimum buffer size for COMPRESSION that is routed to the zEDC Hardware Accelerator for processing.
  • INFMINREQSIZE
    Specifies the minimum buffer size for DECOMPRESSION.
Set the MAXPACK Parameter
Set the MAXPACK parameter to a minimum of 31744. The higher the value for these parameters, the more efficient overall transfer processing becomes.
Set the PACK Parameter
For any transfer, specify PACK=LENGTH to verify that the minimum buffer size requirement for compression on the zEDC is met. If you do not specify PACK=LENGTH, the record size of data in a file must meet the minimum buffer size to move the compression or decompression workload to zEDC.
If zEDC is not available, zlib processing attempts to use the zIIP processor. If that is unsuccessful, zlib processing occurs on a “regular” CP.
Use zLIB Compression Algorithm
zEDC Hardware Accelerator compression services are available
only
for the ZLIB family of compression algorithms (COMPRESS=ZLIB or COMPRESS=ZLIB1 - ZLIB9).
Meet Security Requirements
To be eligible to use the zEDC Hardware Accelerator facility, the USERID under which the transfer runs must have READ access to facility “FPZ.ACCELERATOR.COMPRESSION” as follows:
  • For SECURITY=SAF environments, each individual USERID used to perform data transfers must have READ access granted to the facility.
  • For any XCOM SECURITY= settings other than SAF, the USERID under which the XCOM Started Task runs must have READ access to the facility.
For more information about how to grant READ access, see your security product documentation.
Review zEDC-Related Messages
CA XCOM Data Transport provides unique messages for determining the status and usage of zEDC Hardware Acceleration services. Review these messages and act on them promptly when they require follow-up action.
  • XCOMM0934I
    zEDC hardware acceleration will be used for {compression | decompression}
  • XCOMM0935I
    zEDC hardware acceleration available for zlib  {inflate | deflate} buffers >= nnnnnK
  • XCOMM0936I
    zEDC hardware acceleration detected.  However, minimum  {inflate | deflate} threshold nnnnnK excludes XCOM use
  • XCOMM0937I
    zEDC hardware acceleration not available or not configured for {inflate | deflate}
For any XCOM SECURITY= settings other than SAF, the USERID under which the XCOM Started Task runs must have READ access to the facility.