performanceGuru.com

This blog forms part of the http://performanceGuru.com website which focuses on performance tuning UNIX-like Operating Systems (including Linux).

Tuesday, November 29, 2005

 

Performance: PHP Performance Profiling...

The Linux Journal is running an article about PHP performance profiling. The main technique outlined shows how to identify hotspots in your code and is similar to the techniques you would use to tune any other body of code. Whilst its a nive intorductory articel on the topic it owuld have been nice to see some reference to the dtrace probe points that have been added to PHP.

This does start to touch on some personal thoughts I have been having recently about defining a standard API for inserting probe points into various dynamic languages, enabling authors of such programs to expose interesting profiling information on both dtrace and systemtap (assuming systemtap delivers user space probing), in fact this could just be a general profiling API for all Developers, something a bit like ARM. Anyway some research and serious thought is probably required on my part before I say too much more.


 

Linux: Tuning Oracle Database 10g For ext3 File Systems...

RedHat Magazine has an article this month on the improved performance of ext3 with Oracle 10g when using DIO/AIO under RHEL4 U2. A reasonable article but for me could have done with a little more meat and substance, as to the exact changes that were made in the code and why they caused this improvement, time to consult the changelogs and the code I guess.

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Monday, November 28, 2005

 

Analysis: Queueing Theory Resources...

After watching Sun's recent scalability Webcast in which Bryan Cantrill pointed out that the best method for studying the vertical scalability of systems was to develop a mathematical model. I thought it might be time to trawl the web and see what Queueing Theory resources are out there. So here are a few links for those of you who are interested:

Free Books
Introduction To Queueing Theory
Queueing Theory
A Short Introduction To Queueing Theory
The Practical Performance Analyst

Of these, I can personally recommend the Practical Performance Analyst by Neil Gunther. In the 'free' version of the book he mainly uses the C based PDQ Toolkit, however if you buy the later book Neil has ported PDQ to Perl (its now on CPAN) and details how to use it - I would personally recommend buying the second book.

Related Papers & Articles
Computer Simulation Techniques: The Definitive Introduction!
A General Introduction To Queueing Theory
Queuing Analysis (A Practical Guide for Computer Scientists)
Queueing for Dummies

Any time spent studying this field is likely to pay dividends, particularly as software scaling is likely to be the hot topic of the next few years, as chips move to multicore.


Sunday, November 27, 2005

 

Linux: Introduction To Netcat...

Linux.com has a brief introduction to the GNU Netcat tool which is one of the most usefull adhoc network tools available...

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Linux: New Approaches To Package Management...

Linux.com has this article which explores alternatives to RPM in the Linux world. The article briefly introduces Portage and Conary in particular...


Saturday, November 26, 2005

 

Linux: Shared Subtress...

LWN is carrying the technical documentation from the new shared subtrees patch for the Linux kernel. This feature allows for relationships between the kernel filesystem namespaces to be created. Although the accompanying article indicates that the motivator for this functionality is the ReiserFS files as directories feature (i.e. hard links for directories) and the new filesystems in user space feature, it does not take much imagination to see this as start at implementing zone-like functionality in Linux...

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Sparc: Throughput Computing Paper...

There is an interesting introductory article to CMT & CMP from Sun. Covers the recent advances in the Sparc chipset, introducing the coolthreads technology and the Sparc T1/IV+ chip. From the introduction:

Sun's Throughput Computing initiative is designed to specifically address these seemingly contradictory trends providing radically better levels of application and computational throughput while fundamentally changing the equation on space and power consumption. Chip multiprocessing and Sun's radical chip multithreading (CMT) processors with CoolThreads technology allow individual systems to deliver significantly more throughput in footprints that are the same or considerably less than previous generation systems enabling truly massive levels of simplification and consolidation. Simpler, cooler, and more efficient chip and system designs also dramatically lower both power and cooling bills, prolonging the useful life of many data centers while lowering dependence on shared energy resources. Efficient power and cooling is critical, as a recent survey indicated that data center managers report a 10 percent or more increase in power requirements over the past year and fully 41 percent reported that they anticipated upgrading their power and cooling systems over the next three years.


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Article: Comparing Two High Performance...

Artima have published this article on high performance socket I/O which discusses how-to re-engineer the standard non-asynchronous sockets approach found in most UNIX systems to more closely resemble the asynchronous sockets provided in Windows...


 

Scale My Apps: Strategies and Technologies for Maximum Scalability...

Sun have put together a very good webcast which highlights how they are transitioning their expertise in large NUMA type systems into the challenges of smaller horizontally scaled technologies.

Obviously one of the main thrusts of this webcast is threading, although it was refreshing to hear the chat to be fairly platform agnostic with discussion of both horizontal and vertical approaches being discussed.

One of the things that came across to me in this presentation is that really they are facing the same challenges in the vertical and horizontal environments, its just when you solve them for the horizontal you have to operate in a smaller solution domain and be more creative, as you cannot offload these complex issues to the system hardware.


 

Clarification: Adam To Attend LOSUG...

Adam Leventhal will be attending the LOSUG meeting. My cynical fears that the phrase "aided by" meant dialed in have been allayed by Adam who confirmed he will be attending - see you there (and free Solaris/ free beer - it just keeps getting better)!

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Friday, November 25, 2005

 

Adam Leventhal Makes An Appearance On LUG Radio...

Adam Levanthal is interviewed in the the latest edition of LUG radio. Please be aware that LUG Radio contains quite a lot of swearing and sexual references between interviews, so you are probably not best to play it in the middle of the Office at full volume. Quite a tough interview with the guys asking some fairly direct questions...


Thursday, November 24, 2005

 

LWN: Nexenta & Debian Collide...

Not too surprisingly, the new darling of the OpenSolaris world, Nexenta has re-ignited the license debate and questioning of the motivation for Sun's choice of license. I am no legal expert so I will not comment on that aspect but I do agree with the following sentiment expressed in the article:

I'm amazed at the level of intolerance that's greeting a pretty major contribution to the free software community. There are, what, five major OS/kernels for PCs/workstations these days -- Windows, OS X, Solaris, BSD and Linux. How does it make any sense at all to be hostile to the fact that now four out of those five are free at their core?


Seems to me that this something that needs to be worked out so that the whole FOSS movement can move forward. Maybe I should learn more about the legalities of licensing before I dig too big a hole for myself - its an interesting read...

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Trouble At The Top At Novell...

Stumbled across an interesting article in Business Week when I was trying to make sense of what has been happening at Novell recently. Not sure about which of the executives is correct but I cannot help agree with the sentiment that I would rather see two major Linux players than one. It perhaps would have been nice to see a mention of Sun and OpenSolaris in the article, perhaps if Novell manage to drop the SuSE ball then OpenSolaris will be the born successor and that we might start to think more in terms of a FOSS market than a Linux one, it would certainly cheer up Eric...

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Minix 3 Released...

Version 3 of the famous Minix Operating system, has been released. The core kernel is under 4000 lines of code and it follows a micro kernel approach. There is also an updated version of the classic Tannenbaum book slated, to go with the code. Possibly a useful teaching aid and potentially a real-time O/S?


Wednesday, November 23, 2005

 

London OpenSolaris Meeting...

Another LOSUG meeting has been announced. It will be at the same venue as last time:

Sun Customer Briefing Centre,
45 King William Street,
London EC4R 9AD.

(A Map Courtesy Of Google)

The rough agenda is:

- General - What's new in OpenSolaris
- Technical - "Deeper with DTrace"
- OpenDiscussion(tm?)- Q & A session

The "Deeper With Dtrace" session is 'aided by Adam Leventhal' which I am not sure exactly what that means but he may be involved in some way.

See some of you there - Monday 19th December 2005?

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Tuesday, November 22, 2005

 

Set Of Solaris Networking Summary Slides...

When trawling the web as part of my research into an difference that I have been seeing between the Linux and Solaris TCP implementations I stumbled across this slide deck which provides a decent summary of the current and future state of the Solaris network stack - it was also exceptionally gratifying (as someone who defected to Linux from Solaris a number of years ago), to be able to browse the source and read the code in use in Solaris 10 and it so neat (deliberately ambiguous)!

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New Linux Distributed Debugger...

Stumbled across a new and interesting project on sourceware.org called frysk. Seems like an amalgam of a monitoring system and a debugging framework. Read through the FAQ, looked at the screenshots and signed up to the mailing list. Will try to find some time to see how far the tool has come and if its as useful as it appears, will post updates when appropriate...

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Emerging Compiler Transfoms...

This excellent paper looks at the state of modern compiler transformations, reviews the state of the art ideas in this area and then researches some of the apsects of gcc 4.x...

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Intel Roadmap Analysis...

As the news trickles in that Dell are to start to sell AMD across their entire product line, its interesting to read this analysis at Tom's hardware of Intel's Product Roadmap. The analysis is mainly based around the server platforms that will be delivered in 2006 and the additional value-plays that Intel will make in this area, such as increased RAS and I/O acceleration.

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Monday, November 21, 2005

 

Linux Clustering with Ruby Queue: Small is Beautiful...

An excellent article on using Ruby to build a workload/Grid management system by Ara Howard:

Ruby Queue software package lowers the barriers scientists need to overcome in order to realize the power of Linux clusters. It provides an extremely simple, economic, and easy-to-understand tool that harnesses the power of many CPUs while simultaneously allowing researchers to shift their focus away from the mundane details of complicated distributed computing systems and back to the task of actually doing science. The tool set is designed with a K.I.S.S, research-focused, philosophy that enables any ordinary (non-root) user to set up a zero-admin Linux cluster in 10 minutes or less. It is currently being used successfully in such diverse fields as bio-chemical research at the University of Toronto, geo-mechanical modeling at IGEOSS, and studying the nighttime lights of the world at the National Geophysical Data Center.



 

Tying Together Power, CMP & Performance...

Yet another top article in ACM queue, as part of their series on CMP. This article is from Luiz Andre Barroso, who heads up the Platform Engineering Group at Google. The article goes through some of the economics of CMP adoption and it quite a timely read if you have been seeing the "DataCenter In A Box" and Niagra speculation of late...

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Living With CMT, CMP & SMP...

Richard McDougall has this excellent article published in the ACM Queue covering "Extreme Software Scaling". The years of experience that the Sun performance guys have spent scaling software onto their massive top-end systems is going to become the norm as these techniques hit the mainstream with CMT (Chip Multi Threading), CMP (Chip Multi Processing) & SMP (symmetric Multi Processing)...

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Measuring CPU...

There's a very good post in Adrian Cockcroft's blog discussing the construction and relevance of CPU utilisation figures and the impact of hyperthreading on them...

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SATA Disk Review...

Fourteen offerings from the fast evolving SATA world are covered in this guide from Tom's hardware. Also serves as a useful refernce for constructing your own disk benchmarks...

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Sunday, November 20, 2005

 

Updating Delicious...

After my absence I am updating my delicious links. New articles include (much of my research work is posted to delicious which is available as an RSS feed or as a list on the sidebar of this page):

Architecture: End to End Arguments in System Design...
This paper presents a design principle that helps guide placement of functions among the modules of a distributed computer system. This principle, called the end-to-end argument, suggests that functions placed at low levels of a system may be redundant o
to systems...

Virtualisation: Automating Xen Virtual Machine Deployment...
While consolidating physical to virtual machines using Xen,we want to be able to deploy and manage virtual machines in the same way we manage and deploy physical machines. For operators and support people there should be no difference between virtual and to...

Development: Cocoa Subclasses & Delegates...
In Java subclassing, nearly everything was quite common. So common in fact, that Sun provided generic subclasses in quite a few cases. Objective-C and Cocoa, however, have a different approach. Marcus walks you through the different approaches used in...

Shell: Reading Function & Cursor Keys In A Shell Script...
This month, Chris F.A. Johnson presents Reading Function and Cursor Keys in a Shell Script...

Databases: Learning from The Web...
The Web has much to teach us about managing and modeling distributed data. It's time we began listening.

Databases: Why Your Data Won't Mix...
Making heterogeneous schemas play nicely together has challenged computer scientists for years, but we're on the path to better behavior...

Databases: Managing Semi-Structured Data...
Most of the world's data does not fit into a traditional database structure. Fortunately, work is being done on various fronts to harness this vast information pool...

Development: Pragmatic Exceptions...
A general rule for showing obvious exception messages (such as in a dialog) should be. Show the message only if there is an immediate, reasonable course of action users can take...

Development: Memory Management & Embedded Databases...
Building an infrastructure with opimisation in mind...

Development: Wide-Character Format String Vulnerabilities
Strategies for handling format string weaknesses...

Linux: The SIG11 Problem (Hardware Debugging)...
This FAQ describes what the possible causes are for an effect that bothers lots of people lately. Namely that a linux(*)-kernel (or any other large package for that matter) compile crashes with a "signal 11". The cause can be software or (most likely)...

Virtualisation: Building your own VMWare VMM Management Websites...
SDK Programming - building your own Virtual Machine Management Websites...

Virtualisation: ESX Server Performance Tuning Lab...
VMware ESX Server Performance Troubleshooting...

Embedded: SoC, Function allocation and specification...
The system-on-a-chip (SoC) has emerged as the ideal replacement for multipart chipsets. The SoC design promises a single-chip solution, lower power, less board real estate, simpler integration, and lower part counts -- all of which are clearly quite attra...

Systems Management: The Role Of The Human In Autonomic Systems...
Autonomic computing enables IT systems to manage themselves. The autonomic computing architecture provides a foundation on which self-managing information technology systems can be built...

Grid: Grid architecture in the Telescience Project...
What does it mean to "grid-enable" an end-to-end process? In the first article of this series, we describe the grid-based system architecture developed in the Telescience Project at the National Center for Microscopy and Imaging Research.
to grid virtualisation architecture...

Virtualisation: Windows Virtualisation Technology for Intel Architecture...
The first presentation covers with greater detail what appeared on the public virtualization roadmap webcast, while the remaining two disclose information never appeared till now. So it really worth the read...

Virtualisation: Windows Virtualization Technology for AMD Architecture
The first presentation covers with greater detail what appeared on the public virtualization roadmap webcast, while the remaining two disclose information never appeared till now. So it really worth the read...

Virtualisation: Windows Virtualisation Architecture...
The first presentation covers with greater detail what appeared on the public virtualization roadmap webcast, while the remaining two disclose information never appeared till now. So its really worth the read...

Virtualisation: Architectural Considerations & Other Evaluation Criteria...
A new white paper, Virtualization: Architectural Considerations And Other Evaluation Criteria, describes the operation of virtualization designs and examines the issues...

Virtualisation: Slicing & Dicing Servers...
Part of an emerging family of containment technologies, server virtualization is designed to help reduce server sprawl — the proliferation of individual hardware servers and accompanying management and resource allocation problems...

Performance: Extreme Software Scaling...
Chip multiprocessors have introduced a new dimension in scaling for application developers, operating system designers, and deployment specialists.
to cmt software performance tuning...

Research: TinyDisk...
TinyDisk is a program from saving and retrieving files from TinyURL and TinyURL-like services such as Nanourl. It overlays a write-once-read-many anonymous, persistent and globally shared filesystem...

Storage: Serial ATA Trade Body...
Home page for the SATA-IO trade organisation...

Virtualisation: Developing, Testing & Deploying...
This article shows how VMware software improves testing productivity and eliminates hardware bottlenecks for testing and deployment...


 

Thanks Zen...

After a number of weeks off the Net I am now hooked up with a new service provides, called Zen Internet. So far they seem excellent and extremely competent, had to phone technical support and got through in less than a minute - what a joy...

Catching up on my email and RSS - will be back blogging soon...

Monday, November 07, 2005

 

Still Being DOS'd By UK Online...

Its now been nearly six seeks since I made the mistake of moving to UK Online. I have now been waiting 2 weeks for them to terminate their service so I can order a new service - latest update they messed it up and I will be lucky if I can order another service by mid-November. Thanks UK Online (a wholly owned subsidiary of Easynet for those of you interested)...

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