The C1. 0K problemHelp save the best Linux news source on the web subscribe to Linux Weekly News. Its time for web servers to handle ten thousand clients simultaneously. After all, the web is a big place now. And computers are big, too. You can buy a 1. 00. MHz machine. with 2 gigabytes of RAM and an 1. Mbitsec Ethernet card for 1. Lets see at 2. KHz, 1. Kbytes, and 5. Kbitssec per client. It shouldnt take any more horsepower than that to take four kilobytes. That works out to 0. Those. 1. 00client licensing fees some operating systems charge are starting to. So hardware is no longer the bottleneck. In 1. 99. 9 one of the busiest ftp sites, cdrom. Gigabit Ethernet pipe. As of 2. 00. 1, that same speed is now. ISPs. who expect it to become increasingly popular with large business customers. And the thin client model of computing appears to be coming back in. Internet, serving. With that in mind, here are a few notes on how to configure operating. The discussion. centers around Unix like operating systems, as thats my personal area. Windows is also covered a bit. See Nick Blacks execellent Fast UNIX Servers. In October 2. 00. Felix von Leitner put together an excellent web page. One of his observations is that the 2. Linux kernel really does beat the 2. OS developers food for thought for some time. See also the Slashdot. Felixs results. If you havent read it already, go out and get a copy of. Unix Network Programming Networking Apis Sockets and Xti Volume 1. W. Richard Stevens. It describes many of the IO. It even talks about the thundering herd problem. Last year, Bryce Menzies set a new world record for the longest offroad truck jump using a modified 900horsepower Pro2 truck. The resulting 379. Get the latest health news, diet fitness information, medical research, health care trends and health issues that affect you and your family on ABCNews. In the internet protocol suite, a port is an endpoint of communication in an operating system. While the term is also used for female connectors on hardware devices. Google fired a software engineer yesterday in response to public outrage over the mans 10page screed against women being represented proportionally in tech companies. ABC News Steve Osunsami reports on the storm from Biloxi, Mississippi. Avast-All-Products-Universal-Crack-DLL-Valid-Till-2050-1.png' alt='Ports Of Call License Cracking' title='Ports Of Call License Cracking' />And while youre at it, go read Jeff Darcys notes on high performance server design. Another book which might be more helpful for those. Building Scalable Web Sites by Cal Henderson. Prepackaged libraries are available that abstract some of the techniques presented below. ACE, a heavyweight C IO framework. IO strategies. and many other useful things. In particular, his Reactor is an OO way of doing nonblocking IO, and. Proactor is an OO way of doing asynchronous IO. ASIO is an C IO framework. Boost library. Its like ACE updated for. C. IO framework by Niels Provos. But Lightningonly headphones only work on iOS devices with Lightning ports. To listen to music on anything else, like your computer, or even an older iPhone, you. DriverPack-Solution-Lite-Screenshots.png?resize=825%2C510' alt='Ports Of Call License Cracking' title='Ports Of Call License Cracking' />It supports kqueue and select. Its level triggered only, I think. Niels has. a nice graph of time to handle one event. It shows kqueue and sysepoll. My own attempts at lightweight frameworks sadly, not kept up to date. Poller is a lightweight C. IO framework that implements a level triggered readiness API using whatever underlying. API you want poll, select, devpoll, kqueue, or sigio. TeamViewer-12-Crack-Portable-With-Serial-Key-and-License-Key-Download-Free.jpg' alt='Ports Of Call License Cracking' title='Ports Of Call License Cracking' />Its useful for benchmarks that compare. APIs. This document links to. Poller subclasses below to illustrate how each of the readiness APIs. C IO framework that was my second try. Poller. Its lgpl so its easier to use in commercial apps and. C so its easier to use in non C apps. It was used in some commercial. Matt Welsh wrote a paper. April 2. 00. 0 about how to balance the use of worker thread and. The paper describes part of his Sandstorm IO framework. Cory Nelsons Scale IO library for Windows. Designers of networking software have many options. Here are a few. Whether and how to issue multiple IO calls from a single thread. Dont use blockingsynchronous calls throughout, and possibly use multiple threads or processes to achieve concurrency. Use nonblocking calls e. ONONBLOCK to start IO. OK to start the next IO on that channel. Generally only usable with network IO, not disk IO. Use asynchronous calls e. IO, and completion notification e. IO finishes. Good for both network and disk IO. How to control the code servicing each client. Unix approach, used since 1. OS level thread handles many clients each client is controlled by. GNU state threads, classic Java with green threads. OS level thread for each client e. Java with native threads. OS level thread for each active client e. Tomcat with apache front end NT completion ports thread pools. Reinforced Concrete Design Software. Whether to use standard OS services, or put some code into the. Vx. D. The following five combinations seem to be popular. Serve many clients with each thread, and use nonblocking IO and level triggered readiness notification. Serve many clients with each thread, and use nonblocking IO and readiness change notification. Serve many clients with each server thread, and use asynchronous IOserve one client with each server thread, and use blocking IOBuild the server code into the kernel. This is the traditional favorite. With this scheme, the kernel tells you whether a file descriptor is ready. The name level triggered comes from computer hardware. Jonathon Lemon introduced the terms in his. BSDCON 2. 00. 0 paper on kqueue. Note its particularly important to remember that readiness notification from the. Thats why its important to use nonblocking mode when using. An important bottleneck in this method is that read or sendfile. Same thing goes for memory mapped disk files. The first time a server needs disk IO, its process blocks. This is what asynchronous IO is for, but on systems that lack AIO. IO can also get around this. One approach is to use memory mapped files. IO is needed, ask a worker to do the IO. Jef Poskanzer mentions that. Pai, Druschel, and Zwaenepoels 1. Flash web server uses this trick they gave a talk at. Usenix 9. 9 on it. It looks like mincore is available in BSD derived Unixes. Solaris, but is not part. Single Unix Specification. Its available as part of Linux as of kernel 2. Chuck Lever. in November 2. Vivek Pei et al reported. Flash web server. One bottleneck they found was. Another was the fact that sendfile blocks on disk access. EWOULDBLOCK. when the disk page its fetching is not yet in core. Not sure how you tell the user the page is now resident. The end result of their optimizations is a Spec. Web. 99 score of about 8. GHZ1. GB Free. BSD box, which is better than anything on. There are several ways for a single thread to tell which of a set of nonblocking sockets are ready for IO. Unfortunately, select is limited to FDSETSIZE handles. This limit is compiled in to the standard library and user programs. Some versions of the C library let you raise this limit at user app compile time. There is no hardcoded limit to the number of file descriptors poll can handle. Some OSs e. g. Solaris 8 speed up poll et al by use of techniques like poll hinting. Niels Provos for Linux in 1. This is the recommended poll replacement for Solaris. The idea behind devpoll is to take advantage of the fact that often. With devpoll, you get an open handle to devpoll, and. OS just once what files youre interested in by writing to that handle. It appeared quietly in Solaris 7. Sun. at 7. 50 clients, this has 1. Various implementations of devpoll were tried on Linux, but. Linux is not recommended. Caution the example is for Linux devpoll, might not work right on Solaris. This is the recommended poll replacement for Free. BSD and, soon, Net. BSD. See below. kqueue can specify either edge triggering or level triggering. Readiness change notification or edge triggered readiness notification. It then assumes you. EWOULDBLOCK error on a send, recv, or accept call, or a send or recv transfers. When you use readiness change notification, you must be prepared for spurious. This is the opposite of level triggered readiness notification. Its a bit less forgiving of programming mistakes, since. Nevertheless, I have found that edge triggered readiness notification. Open. SSL easier, so its worth trying.