Sun's T5440 Server Is Built To Multitask

CMT technology ramps up CPU performance, but not speed.
Need to multitask? Sun's latest multicore server, the Sparc Enterprise T5440, runs rings around more expensive devices when performing a lot of tasks concurrently. It's ideal for databases and virtualization and excels at encrypting and decrypting data thanks to on-board security co-processors.

With the T5440, powered by UltraSparc T2 Plus chip multithreading (CMT) chips, Sun has blurred the distinction between traditionally lower-end T series and higher-end M series devices. Although single-thread performance is still higher in the M series, the UltraSparc T2 Plus CMT turns in performance above its pay grade thanks to its higher concurrency of operations.

Our $132,995 T5440 test server came with four processors. Each processor holds eight cores, and each core sports as many as eight threads, two of which can be active at any time. Count 'em: As many as 64 active threads per processor means a top level of 256 threads active in the system. These threads are exposed as CPUs to the operating system. When we checked output using Sun's prtdiag system information tool, a huge list of 256 CPUs was returned. Put another way, the T5440 focuses on getting a lot of things done at one time, albeit not necessarily at top speed.

CLAIM:  With the Sparc Enterprise T5440, Sun Microsystems aims to pack a massively scalable system into one box priced less than comparable systems. The T5440 is powered by UltraSparc T2 Plus CMT, which takes CPU performance to new heights. Sun has groomed the T5440 for heavy data center chores and virtualization.

CONTEXT:  Most major hardware vendors now offer multiprocessor systems to answer demand for high-performance, lower-cost servers that can handle large loads and easily virtualize. Building on its CMT processors, Sun's T5440 delivers a high-throughput server that packs 256 threads.

CREDIBILITY:  The $132,995 T5440 server will excel anywhere throughput is more important than CPU speed--in those areas, the T5440 is rewriting the record book. Database workloads--in particular, Oracle and SAS environments--are well-suited to the T5440's CMT technology.
When dealing with a CPU with this much potential horsepower, it's important to feed it the data it needs. The UltraSparc T2 Plus CPU has 4 MB of high-speed Level 2 cache. The CPU can use that memory quickly, but it takes a relatively long time to get data from the main memory. Under normal workloads, having each thread idle 75% of the time is an asset--it masks the latency of moving memory into the Level 2 cache.

An extremely common task for servers is to encrypt and decrypt data. To help with this, the UltraSparc T2 Plus has eight security co-processors per CPU, one per core. This allows the CPU to off-load cryptographic functions to the co-processor, greatly increasing performance. Most common algorithms are supported.

Configured with the standard 4-GB FB-DIMMS, the T5440 can expand to 256 GB of memory. The T5440 also can be ordered to ship with 8-GB FB-DIMMS for a maximum of 512 GB of main memory. The T5440 ably dealt with high-concurrency server workloads in our tests, particularly database chores. However, it's important to note that single-threaded loads will not effectively utilize the T5440's processors.

The T5440's parallel capacity also makes it a good choice for virtualization. Sun's virtualization technology is Logical Domains (LDoms). Comparable to Citrix's Xen, LDoms are paravirtualized environments and require the cooperation of the guest OS to work. Sun supports only Solaris 10 in LDoms, but if your interest is in Linux, there's a large base of community support for running Sparc Ubuntu inside an LDom. Unlike Xen, however, LDoms segment the physical resources of the machine. Each domain is allocated one or more threads, optionally one or more crypto units, and, optionally, a real disk. This more rigid approach increases performance by keeping a particular domain's threads and memory closer to the CPU that has been assigned to it.

We found the all-purpose "ldm" LDom-controller command easy to use, and we had our first LDom up and running within minutes. Adding and removing them also was a snap.

While VMware ESX 3.5 can scale to four virtual CPUs on an x86-based Sun Fire T4150, LDoms can scale far beyond that. With 256 virtual CPUs in the T5440, we could make hundreds of LDoms with one or two CPUs, or fewer LDoms with many more CPUs.

To better serve 10 Gigabit Ethernet, two of the PCIe slots in the T5440 have 10 Gigabit Attachment Unit Interface (XAUI) headers built in. This means that instead of PCIe cards, you can install two 10 Gigabit Ethernet cards into those slots. As XAUI runs natively at 10 GB, it vastly outperforms PCIe. As the T5440 has 8x PCIe support, each PCIe slot can operate at a relatively meager 2 Gbps.

Better consider your software options, too.
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Everyone hates going to the data center (except to hide, of course). It's loud, uncomfortable, and now--thanks to remote management--unnecessary. Sun has extended its Advanced Lights Out Management (ALOM) and Embedded Lights Out Management (ELOM) support into the new Integrated Lights Out Management (ILOM).

The ILOM can be managed over the network via IPMI 2.0, SNMP, SSH, HTTP(S), or a Serial port. On the whole, we found the experience quite similar to ELOM, although some functions have moved. There's an ALOM syntax compatibility mode if you're more familiar with that. Sun says it's working to standardize on the ILOM syntax.