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How Google Uses Linux

Posted by timothy on from the rebasing-not-freebasing dept.

postfail writes 'lwn.net coverage of the 2009 Linux Kernel Summit includes a recap of a presentation by Google engineers on how they use Linux. According to the article, a team of 30 Google engineers is rebasing to the mainline kernel every 17 months, presently carrying 1208 patches to 2.6.26 and inserting almost 300,000 lines of code; roughly 25% of those patches are backports of newer features.'

3 of 155 comments (clear)

  1. Release the patches already by Dice · · Score: 5, Interesting

    They monitor all disk and network traffic, record it, and use it for analyzing their operations later on. Hooks have been added to let them associate all disk I/O back to applications - including asynchronous writeback I/O.

    I. Want. This.

  2. Low memory conditions by jones_supa · · Score: 5, Interesting

    Google makes a lot of use of the out-of-memory (OOM) killer to pare back overloaded systems. That can create trouble, though, when processes holding mutexes encounter the OOM killer. Mike wonders why the kernel tries so hard, rather than just failing allocation requests when memory gets too tight.

    This is something I have been wondering too. Doesn't it just lead to applications crashing more often than them normally reporting they cannot allocate more memory?

  3. Re:Is it worth it? by dingen · · Score: 5, Interesting

    Ooooh... efficiency.. I'm curious what the net savings is.. compared to buying more cheap hardware.

    We're talking about Google here. They have dozens of datacenters all over the globe, filled with hundreds of thousands of servers. Some estimate even a million servers or more.

    So lets assume they have indeed a million servers and they need 5% more efficiency out of their server farms. Following your logic, it would be better to add 50,000 (!) cheap servers which consume space, power and require cooling and maintenance, but I'll bet you paying a handful of engineers to tweak your software is *a lot* cheaper. Especially since Google isn't "a project" or something. They're here for the long run. They're here to stay and in order to make that happen, they need to get the most from their platform as possible.

    --
    Pretty good is actually pretty bad.