SGI's Octane

Ralph Barker

This spring, all major UNIXworkstation vendorsrefreshed their product

lines. Digital Equipment Corp.

(DEC) started shipping a 600MHzversion of its Alpha CPU in a n e w, less expensive, personal-workstation architecture. Hewlett-Packard shipped new systems atboth ends of its workstation line-

up, some using its economicalPA7300LC CPU and others withits 64-bit PA8000 chip. SunMicrosystems and most Sun-clonemakers began shipping dual-CPUSMP UltraSPARC systems. Mean-while, Silicon Graphics Inc. (SGI)began quantity shipments of twonew workstations: a new entry-level machine, the O2 (see ourreview in the May 1997 issue, p.49), and a new high-end system,the Octane. The Octane uses the64-bit Mips R10000 CPU, is dual-processor SMP capable, and ispositioned between SGI’s popularI n d i g o2 systems and its Onyx2

series of graphics supercomput-ers. In this review, we examine atwo-CPU SMP configuration of theO c t a n e .

Of NoteThe highly modular architec-

ture of the Octane is another representation of SGI’s concen-tration on minimizing latencyand improving throughput withinits system designs. Similar to other systems of contemporarydesign, the Octane uses a non-

S G I ’s OctaneWo r k s t a t i o nU n l i ke the economy-minded O2, the Octane is

designed for performance, using dedicated subsys-

tems and dual R10000s to power advanced graphics.

August 1997 51 Unix Review

blocking, crossbar- s w i t c h i n gmatrix rather than a conventionalshared bus. The Octane’s cross-bar has eight ports, seven ofwhich are used: one for the twopossible CPUs, one for graphics,three for XIO slots, one for an I/Obridge, and one for a PCI bridge.The crossbar design enablessimultaneous communicationbetween pairs of subsystemswithout the bus contention asso-ciated with shared-bus architec-tures, thereby decreasing latencybetween operations and signifi-cantly improving throughput. SGI rates the peak bandwidth at 1.0GB/sec for memory, and1.6GB/sec peak, or 1.2GB/sec sustained, for communicationsbetween subsystems.

To maximize system perform-ance, the Octane uses dedicatedhardware, such as special texturememory, that is optimized for specific operations. This designapproach contrasts with that usedin the O2, where an innovativeUnified Memory Architecture(UMA) was chosen as a means of minimizing system cost. Theseparate geometry engine on theOctane’s graphics boards, forexample, accesses dedicatedframe-buffer memory and can beequipped with an optional 4MBtexture cache. While the O2 wasdesigned to provide extensivegraphics capabilities at the lowestcost, the Octane was built for per-formance; cost considerationswere secondary.

Three graphics options areavailable for the Octane: SI, SSI,and MXI. The single-slot SI cardprovides a single geometry-enginep r o c e s s o r, while the SSI includestwo geometry engines and tworaster engines, filling two XIOslots. An optional 4MB texturememory can be added to eithercard. The MXI card is essentiallyan SSI card with the 4MB texturememory pre-installed. Graphicslibraries supported by the cards

include OpenGL, Open Inventor,IRIS Performer, and ImageVi s i o n .

Built-in audio support on theO c t a n e ’s motherboard includesconventional microphone andstereo speaker jacks, desktoploudspeakers with a headphonejack, stereo digital coaxial andoptical I/O connectors, and 8-channel Alesis Digital AudioTape (ADAT) optical I/O. OptionalPCI audio cards provide addition-al ADAT optical I/O, plus stereo24-bit AES3-1992 I/O (AudioEngineering Society), video-composite sync loop-through forlocking audio sample rates toPAL/NTSC video, and sample-accurate synchronization withother digital media subsystems.Also note that the three PCI slotsin the Octane are 64-bit, provid-ing long-term flexibility for PCIoptions.

Although the Octane we testedcame equipped with dual 195MHzMips R10000 CPUs, you also canpurchase the system with a singleCPU (either 175MHz or 195MHz)and upgrade it to SMP later. Theexpansion of single- to dual-CPUrequires replacement of the single-CPU daughter card with a dual-CPU card. Other expansionoptions include up to three 31⁄2-inch hard disks and up to fourXIO option cards. Advancedgraphics options consume two XIOslots, leaving two slots availablefor other high-bandwidth cardssuch as Ultra SCSI adapters andnetwork cards (Fibre Channel,100Base-TX, ATM, and HIPPI aresupported). PCI options includethe audio cards mentioned earlierand various networking cards,including ATM, FDDI, ISDN, HIPPI,and token ring.

In our review of the O2, wecriticized the design of the desk-top system for having only a CD-ROM drive and not includinga writable removable media bay(for example, a floptical drive).The Octane lacks both a CD-ROM


Octane WorkstationSilicon Graphics Inc.2011 N. Shoreline Blvd.Mountain View, CA 94043(415) 960-1980(415) 961-0595 faxhttp://www.sgi.com

Tested Configuration: Dual Mips R10000CPUs, 195MHz; 32KBd, 32KBi primarycache, 1MB L2 cache; 384MB ECCRAM, expandable to 2GB; 4.2GB 31⁄2-inch Ultra SCSI hard disk; auto-sensing10Base-T/100Base-TX Ethernet port;two serial ports (450Kbps, DB-9); oneparallel port (bidirectional); two UltraFast-Wide SCSI channels; one externalhigh-density 68-pin connector; analogaudio I/O port (RCA); 8-channel, 24-bitA D AT optical digital I/O; microphoneand headset jacks; self-powered exter-nal stereo speakers; MXI graphicsaccelerator; IRIX 6.4 pre-installed andbundled with collaboration and connec-tivity software; 20-inch color monitor.

Price as tested: $70,995

Options: O2 digital video camera, S-Video and composite video I/O; various XIO and PCI board options;lower-cost SI, SI with texture, and SSIgraphics options. Base price for single-CPU 175MHz system with 64MB RAM,2GB disk, SI graphics: $24,995.

Evaluation: The Octane’s excellentdesign is complemented by the robust -ness of IRIX 6.4 and a strong array ofcollaboration, connectivity, and multi-media software. The Octane’s CPU per-formance is good, and its graphicsperformance is excellent.

CIRCLE NO. 250 ON INQUIRY CARD

drive and other removable mediabays in the main chassis, whichinitially struck us as a gravedesign blunder. Our discussionwith SGI about this apparentdesign flaw suggested otherwise.SGI representatives indicated thatthe company surveyed potentialcustomers and found that mostwould be placing the Octane onthe floor, rather than on theirdesktops. That led SGI to supportonly external removable-mediaperipherals that could be placedconveniently on the desktop withthe monitor and keyboard.

O p e r a t i o nThe Octane runs IRIX 6.4, a

full 64-bit operating system thatalso is used for SGI’s Onyx2

graphics supercomputers andOrigin servers, and that is binary-c o m p a t i b l e with IRIX 5.3 and 6.xapplications. This is in contrast tothe O2, which runs IRIX 6.3, a 32-bit implementation used to mini-mize the expense of hardware-levelsupport for 64-bit binaries. SGIhas indicated that an all-platformsrelease of the operating system isforthcoming. The unified versionof the operating system shouldsimplify system administrationwithin organizations that use vari -ous SGI systems.

We found IRIX 6.4 to be stableboth during our benchmark runsand in general use of the system.The user interface is consistentwith earlier releases of the operat-ing system, and the array of bun-dled software will be familiar toSGI users. The Octane’s softwarecomplement includes several collaboration packages (AdobeAcrobat Reader, Cosmo Player,InPerson, Netscape Navigator, andWebMagic, among others), connec-tivity software (XFS and ISDN/PPPsupport, with options for NovellNetWare and Xinet AppleTalk sup-port), and various digital-mediatools (including Media Player,Media Recorder, Media Convert,

Movie Maker, Sound Track, andCD/DAT Player). SoftWindows95from Insignia Solutions (SantaClara, CA) also is available as anoption for users who want to runWindows 95 software on theirOctane.

Documentation for the Octaneis similar to that of other SGIworkstations. Printed documenta-tion is limited to a 318-page own-er’s guide that provides detailedinstructions for maintenance andupgrade procedures. This wire-bound manual is well-illustratedand easy to understand. Onlinedocumentation includes SGI’s IRISInSight bookshelf and its easy-to-use graphical interface.

Perfo r m a n c eWe subjected the Octane

to our usual battery of SPEC,

SPECrate, andVi e w p e r fb e n c h m a r k s .(See thesidebar onpage 54 formore detailedinformation onbenchmarks and review criteria.)Our SPEC runs produced scoresof 17.2 for SPECfp95 and 9.4for SPECint95, with the system in multiuser mode and the stan-dard graphical interface running.These scores are slightly lowerthan those of the high-end500MHz DEC AlphaStation500/500 (20.4 for SPECfp95 and15.0 for SPECint95) and those of the 180MHz Hewlett-PackardHP Visualize C180-XP (18.7 for SPECfp95 and 11.8 forSPECint95). The Octane rates


Inside The OctaneF I G U R E 1

substantially higher than Sun’sUltra 2 Creator model 2200, how-e v e r, which has published scoresof 12.9 for SPECfp95 and 6.9 forS P E C i n t 9 5 .

Our SPECrate scores for theOctane are 275 for SPECfp_rate95and 164 for SPECint_rate95. Sinceneither DEC nor HP has dual-CPUversions of its high-end worksta-tions available, we used dual-CPUscores for servers from those two

companies for comparison. DEC’sAlphaServer 4100, equipped withtwo 466MHz 21164 CPUs, has published scores of 301 for SPEC-fp_rate95 and 250 for SPECint_-rate95. The HP 9000 K460 server,using dual 180MHz PA8000 chips,has published scores of 297 and212, respectively, for those bench-marks. Both the DEC and HP serverscores are higher than those of the Octane, and the graphs (see

Figure 2) show a similar relation-ship between the SMP SPECratescores and those of the single-threaded SPEC benchmark results.Sun has not published SPECrateresults for its dual-processor Ultraworkstation, so we used scores fromour review of the Tatung COMP-station U2200 workstation (see theJuly 1997 issue, p. 59) for compari-son. Based on SPEC comparisons,the Sun Ultra 2 Creator model 2200


uring the last several years,

vendors have used a variety of

benchmarks to measure the graphics

performance of their systems. Most of

these benchmarks exercise various low-

level graphics primitives, such as 2-D

and 3-D vectors, meshed triangles,

quadrilaterals,and so forth.

Unfortunately, different vendors have

used different sets of benchmarks,mak-

ing direct graphics-performance com-

parisons less than optimal. Additionally,

the low-level graphics-primitive per-

formance reflected by these benchmarks

may not be representative of the sys-

tem’s actual performance when using

real-world applications.

In contra s t , the new OpenGL Pe r-

fo rmance Chara c te rization (OPC) sub-

c o m m i ttee Viewperf bench m a rks te s t

the syste m ’s OpenGL re n d e ring perfo rm-

ance with respect to viewsets submitte d

by independent soft wa re vendors (ISV s )

of actual graphics applications. A l t h o u g h

Viewperf test data for many existing

s y s tems is not yet ava i l a b l e ,O p e n G L

has been licensed by most major syste m

m a n u fa c tu rers and appears to be grow-

ing in popularity as the de fa c to stan-

d a rd for many graphics and visualization

a p p l i c a t i o n s . As such , Viewperf is re ga rd-

ed as more re p re s e n t a t i ve of the sys-

te m ’s perfo rmance when used with

a c tual applications.

Viewperf parses command lines for

instructions regarding rendering state

and applies those states to the specified

data sets, converting the data sets into

a format that can be traversed using

OpenGL rendering calls. Viewperf then

renders the graphic for a specified

amount of time or number of frames,

with animation between frames, and

outputs the result.When run,Viewperf

is used with viewsets developed by

ISVs of actual graphics applications.

Viewsets,submitted by ISVs and

approved for use by OPC,thus reflect

real-world performance that is charac-

teristic of the nature of a particular ISV’s

application.Currently, five approved

viewsets are used in conjunction with

the Viewperf benchmark:Evans &

Sutherland Computer Corp.’s (Salt Lake

City, UT) CDRS, IBM’s Visualization Data

Explorer, Intergraph’s (Huntsville,AL)

DesignReview, Lightscape (Light-01)

from Lightscape Technologies Inc.(San

Jose,CA), and Advanced Visualizer

(AWadvs-01) from Alias Wavefront

(Santa Barbara, CA).

Evans & Sutherland’s CDRS applica-

tion is used for industrial design and

modeling. CDRS lets the user create

concept models of items with complex

exterior shapes,such as cars,appli-

ances, and consumer-electronics

devices.The CDRS viewset, CDRS-03,

combines several tests that are weight-

ed to reflect typical usage within the

application. IBM’s Visualization Data

Explorer (viewset DX-03) is a general-

purpose application for the visualization

of scientific data.

Intergraph’s DesignReview applica-

tion (DRV-04) is used for plant-design

models consisting of complex I-beam,

pipe,and equipment layouts,as well

as for tracking actual progress during

construction.The model used in the

DRV-04 viewset is a subset of an actual

offshore oil-production platform located

in the North Sea.The Light-01 viewset

from Lightscape Technologies Inc. com-

bines proprietary radiosity algorithms

with a physically based lighting inter-

face to simulate global illumination

effects within a particular environment.

The Advanced Visualizer viewset

(AWadvs-01) from Alias Wavefront per-

forms various 3-D animation tests based

on that company’s 3-D animation tools,

including free-form 3-D surface render-

ing combined with imported motion

data.

For a more complete description of

these viewsets, see the OPC Web site

at http://www.specbench.org/gpc/opc

.static/index.html.

Source code for Viewperf is publicly

available at ftp://ftp.specbench.org/

dist/gpc/opc/viewperf.

U N I X R E V I E W L A B S

Benchmarking Graphics PerformanceD

should have SPECrate scores simi-lar to those of the Tatung machine.The Tatung U2200 produced aSPECfp_rate95 score of 164 and a SPECint_rate95 score of 110 inour tests.

Although the SPEC bench-marks provide an interesting datapoint for general CPU operation,the OpenGL-based Vi e w p e r fbenchmarks are more closelyrelated to the intended use of theOctane. Our Viewperf results forthe Octane (48.4 for CDRS-0 3 ,13.8 for DX-03, 8.2 for DRV- 0 4 ,1.5 for Light-01, and 16.6 forAWadvs-01) are consistently high-er than the published scores forthe DEC AlphaStation 500/500equipped with DEC’s high-end4D60T graphics accelerator. TheDEC system’s scores were 46.5,11.3, 6.3, 1.3, and 9.6, respec-t i v e l y, for the same tests. Sun haspublished Viewperf scores foronly its 200MHz Ultra 1 Creator3D workstation, and then for onlythe CDRS-03 (33.2) and DX-03(6.6) tests. HP has yet to publishViewperf scores for any of itsPA8000-based workstations.

R e m e m b e r, Viewperf is a sin-gle-threaded benchmark and does not take advantage of dual-processor capabilities. Thus, thecomparisons of our dual-CPUresults on the Octane to single-CPU systems from DEC and Sunare reasonably valid, even if notperfectly so.

H ow It RatesWe find the design of the

Octane to be generally excellent.The Octane’s highly modulararchitecture provides easy accessto all of the system’s subassem-blies, greatly simplifying mainte-nance and upgrade procedures.Where design issues were bal-anced between cost and perform-ance, we think SGI made the rightchoice for the Octane in givinggreater weight to performanceconsiderations. While we still

think a high-end workstationshould include bays for a strongcomplement of removable media,we give SGI credit for consultingcustomers during the designphase. In-chassis bays for remov-able media would be significantlyless convenient than externaldevices if the system is placed onthe floor, rather than on the desk-top. Our one misgiving is that theSMP model places both CPUs on a single card, thus requiring thecomplete replacement of the sin-gle-CPU daughter card during an

upgrade. While there likely areperformance and XIO slot-usageissues solved by the dual-CPUcard, having two CPU-card slots

might providebetter invest-ment protec-tion forbuyers ofs i n g l e - C P Usystems. Werate the Octane’sdesign as excellent, nonetheless.

The Octane’s installation proce-dures and documentation are consistent with, or better than,industry standards. The Octane’sIRIS InSight library of online docu-mentation continues to be the best

and easiest to use among UNIXworkstations, although HP and Sunare not far behind. Both categoriesrate excellent on our scale.


Expandability in the Octanecould be improved only by at a l l e r, more expansive chassis.

As noted earlier, the Octane willaccommodate up to three internal9GB hard disks. We also liked thefact that the Octane has threeslots for 64-bit PCI cards, provid-ing buyers with potentially morecost-effective choices of commod-ity-level option boards. The arrayof high-end audio connections onthe motherboard also is impres-sive and enables various high-end professional multimedia-production capabilities withoutthe installation of option cards.We rate the Octane’s expandabili-ty as excellent.

Operation of the Octane duringour testing was flawless. The IRIX6.4 operating system is stable androbust and is complemented by anextensive array of bundled collabo-

ration and connectivity software.Although SGI has not adopted the industry-standard Common

Desktop Environment (CDE), themultiplatform ease-of-use issuessolved by CDE are less critical in environments where the Octaneis likely to be used. The Octane isnot a general-purpose UNIX work-station, for which we consider thelack of CDE to be a problem. TheOctane’s operation earns anotherexcellent rating.

During testing of the Octaneand in conversations with SGIengineers, we discovered that per-formance was a critical factor inthe design objectives of the engi-neering team. The 195MHz MipsR10000 CPU scores well on theSPEC benchmarks, even if some-what behind competing chips fromDEC and HP. The Octane substan-tially outperformed the dual-CPU

(albeit lessexpensive)model fromSun, how-ever. TheOctane’sViewperf scoresalso were impres-sive, coming in somewhat higherthan those of the 500MHz, high-end DEC workstation, and sub-stantially higher than the SunUltra 1’s scores. Balancing betweenCPU and graphics performance, werate the Octane’s performance asgood. Application benchmarks forspecific uses of the Octane mightprove even better, however.

The Octane is a worthy succes-sor to the popular Indigo2 at thehigh end of SGI’s workstation line.Although the Indigo2 remains inthe SGI lineup, it is definitely out-classed by the Octane’s designand capabilities. We rate theOctane excellent overall, parti-cularly considering the applica-tions for which the machine wasdesigned. UR

Ralph Barker is technical editorfor UNIX Review. He can bereached at [email protected].


Silicon GraphicsOctane Wo r k s t a t i o n

Design

Installation

Documentation

Expandability

Operation

Performance

Overall

How It Rates

P o o r Av e r a g e G o o d E x c e l l e n t

SGI's Octane

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