Performance and Scalability Enhancements

This section describes new tools in the Solaris 8 operating environment for monitoring and improving system performance.

IA: Added Support for PAE Mode

With the release of Pentium Pro, Intel introduced a mode called Physical Address Extension (PAE) on its advanced processors. By using PAE, Solaris Intel Platform Edition can address up to 32 Gbytes of physical memory. Individual processes are still limited to a maximum of 3.5 Gbytes of virtual address space.

PAE mode enables the user to run multiple instances of databases and memory-intensive applications, and to support large numbers of online users on a machine.

It is best to use PCI disk controllers that support Dual Address Cycle (DAC) in your machine because they can transfer data to and from any physical location. Other cards are limited to 4 Gbytes of physical memory, and as a result performance may slow down because the system needs to copy additional memory to transfer data.

Some device drivers are not yet able to take advantage of PAE mode. Sun has tested PCI device drivers written by Sun on IA based machines with more than 4 Gbytes of memory. Sun's OEM partners intend to test their machines with devices they supply on IA based machines with more than 4 Gbytes of memory. In some cases however, if you add a third-party device driver to your system, it may become unstable, and panics and data corruption may result. If your system becomes unstable and you need that driver, you must disable PAE mode support. For more information, see the Solaris 8 (Intel Platform Edition) Device Configuration Guide.

This feature was first available in the Solaris 7 3/99 release.

apptrace

A new application debugging tool, apptrace enables application developers and system support personnel to debug application or system problems by providing call traces to Solaris shared libraries, which may show the series of events leading up to a point of failure.

The apptrace tool provides more reliable call-tracing than the previously available sotruss command. It also provides better display of function arguments, return values, and error cases for any Solaris library interface.

By default, apptrace traces calls directly from the executable object, specified on the command line, to every shared library the executable depends on.

For more information, see the man page apptrace(1).

SPARC: busstat

A new system monitoring tool, busstat provides command line access to the bus-related hardware performance counters in the system. It enables the gathering of system-wide bus performance statistics directly from the system hardware. The current list of supported hardware is SBus, AC and PCI devices. These are all SPARC system devices. Currently, there are no IA supported devices.

The busstat command enables the measurement of system-wide statistics such as memory bank reads/writes, clock cycles, number of interrupts, streaming DVMA read/write transfers and so on.

Superuser can use busstat to program these counters. Other users can only read counters programmed previously by superuser.

The busstat command lists the devices in a system that are found to support these hardware performance counters. If no supported devices are found in the system, the following message is displayed:

busstat: No devices available in system. 

For more information on using this monitoring tool, see the man page busstat(1M).

Faster Boot for Servers

In the Solaris 8 operating environment, large servers now require significantly less time to boot. As a part of the boot performance improvement, the operating system probes for SCSI devices in parallel. Some old dual-port SCSI devices do not support parallel probing and should be removed from the system before installing or upgrading to the Solaris 8 operating environment.

New Alternative to poll() Interface

/dev/poll is a second form of polling for the completion of I/O events that provides much higher performance when a very large number of events must be polled for on file descriptors that remain open for a long time. This feature supplements poll(2); it does not replace poll(2).

For more information, see the System Interface Guide.

This feature was first available in the Solaris 7 5/99 release.

prstat

The prstat utility iteratively examines all active processes on the system and reports various statistics based on the selected output mode and sort order. prstat can also be used to report microstate accounting information and to summarize CPU and memory usage.

For more information, see the man page prstat(1M).

IA: Xeon Enhancements

To maximize performance, Solaris 8 Intel Platform Edition now supports the Page Attribute Table (PAT) feature of IA 32-bit processors (Pentium II and Pentium III). This support enables a device driver writer to take advantage of the write combining feature for a device that can exploit write combining, even if the BIOS does not set up the device for write combining.

For more information, see Writing Device Drivers.