Posted by Coder.
Mar
2
Posted by Coder.
Computer glitch made market drop seem worse
The problem began at 1:50 p.m Tuesday amid heavy selling and caused a 70-minute time lag in calculating the value of the DJIA, according to a statement from Dow Jones Indexes. A system that feeds market data to the computer calculating the DJIA suddenly began experiencing delays. “While the DJIA was still being calculated and disseminated, the calculator was not receiving the underlying component prices of the DJIA on a timely basis.”
When …
Mar
2
Posted by Coder.
CodePlex – PerfTesting
…insightful and practical [guide] around doing performance testing…
Jan
29
Posted by Coder.
Inside MySpace.com
MySpace started small, with two Web servers talking to a single database server. Originally, they were 2-processor Dell servers loaded with 4 gigabytes of memory, according to Benedetto …But at 500,000 accounts, which MySpace reached in early 2004, the workload became too much for a single database…. closing in on 2 million, the service began knocking up against the input/output (I/O) capacity of the database servers… The next database architecture was built around the concept of vertical partitioning, with …
Dec
20
Posted by Coder.
Unlocking Concurrency
Unlike coarse-grained locking, transactions can provide scalability as long as the data-access patterns allow transactions to execute concurrently. The transaction system can provide good scalability in two ways:
It can allow concurrent read operations to the same variable. In a parallel program, it’s safe to allow two or more threads to read the same variable concurrently. Basic mutual exclusion locks don’t permit concurrent readers; to allow concurrent readers, the programmer has to use special reader-writer locks, increasing the program’s complexity.
It …
Dec
20
Posted by Coder.
A Conversation with John Hennessy and David Patterson
KUNLE OLUKOTUN: There are many other issues beyond performance that could impact computer architecture. What ideas are there in the architecture realm, and what sort of impact are these other nonperformance metrics going to have on computing?
JOHN HENNESSY: Well, power is easy. Power is performance. Completely interchangeable. How do you achieve a level of improved efficiency in the amount of power you use? If I can improve performance per watt, I can add …
Nov
28
Posted by Coder.
Identifying MySQL slow queries | MDLog:/sysadmin
… steps in optimizing and tuning mysql is to identify the queries that are causing problems. How can we find out what queries are taking a long time tocomplete? How can we see what queries are slowing down the mysql server? Mysql has the answer for us and we only need to know where to look for it…
Oct
30
Posted by Coder.
Jon Masamitsu’s Weblog : Weblog
The garbage collector tracks the average of the rate of promotion of live objects from the young generation into the tenured generation. If the average exceeds the free space in the tenured generation, the next time the young generation fills up, a full collection is done instead of a minor collection.
There are some caveats to this, read on…
Oct
16
Posted by Coder.
The NY Times has lengthy piece on Friendster’s business and technical problems.
Wallflower at the Web Party – New York Times
The company hired yet another chief of engineering, who laid down the law: at least 80 percent of his people would work on performance and stability issues until the Web site worked as well as it should.“In the past, we had often chosen the more exotic solution over the more simple solution,†Mr. Lindstrom said. Trailblazing a new field like social …
Oct
11
Posted by Coder.
David Dice’s Weblog : Weblog
Just as Java removed explicit memory management from C and C++, I expect that the next generation of programming languages may remove threads and locking as we know it today. Explicit threading will still be available, of course, but ideally I’d like to see the world switch to model where, by default, threads are managed by the runtime environment.
Sep
27
Posted by Coder.
EETimes.com – Google, Intel call for efficient PC power supplies
At the Intel Developer’s Forum in San Francisco on Tuesday, Intel CTO Justin Rattner invited Google engineer Luiz Barroso on stage to call for more efficient PC power supplies.
Noting that the power supply is often the component that consumes the most energy in current PCs, Barroso highlighted findings from a newly published Google white paper.
The paper, >“High-efficiency power supplies for home computers and servers,” by Google engineers Urs Holzle …