Performance-Tuning the Sync/Stream Manager

The Sync/Stream Manager is comprised of two modules: SSMDD.SYS and SSM.DLL. SSMDD.SYS is the Ring 0 device driver of the Sync/Stream Manager. Its syntax is as follows:

DEVICE=─┬─────────┬──┬────────┬── SSMDD.SYS ──┬──────────┬────┤
        └─ drive ─┘  └─ path ─┘               ├─ /S:sss ─┤
                                              ├─ /P:ppp ─┤
                                              ├─ /H:hhh ─┤
                                              ├─ /Q:qqq ─┤
                                              └─ /E:eee ─┘

Parameters:

• S:sss
  Specifies the number of streams that can be created at the same time. Values range from 1 through 64. The default value for machines with more than 8MB of memory is 12. The default value for machines with 8MB of memory or less is 6.
  /P:ppp
  Specifies the number of processes that can create streams at the same time. Values range from 1 through 64. The default value for machines with more than 8MB of memory is 12. The default value for machines with 8MB of memory or less is 6.
  /H:hhh
  Specifies the maximum amount of heap space (KB) that will be used. Values range from 16 through 256; the default value is 64.
  /Q:qqq
  Specifies the size of the event queue (per process). Values range from 2 through 1024; the default value is 64.
  /E:eee
  Specifies the number of events that can be enabled (per stream). Values range from 1 through 1024. The default value for machines with more than 8MB of memory is 32. The default value for machines with 8MB of memory or less is 20.

  Note: The DEVICE=SSMDD.SYS statement must appear as the first Ring 0 stream handler statement in the CONFIG.SYS file.

  Sync/Stream Resource Limits

  • The maximum number of streams is 64.

  • The maximum number of streams in a sync group is 64.

  • The maximum number of processes controlling streams is 64.

  • The maximum size of Sync/Stream Manager event queue per process is 1024 entries.

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