Introduction to FreeBSD 7.0

Introducing FreeBSD 7.0Kris KennawayThe FreeBSD Projectkris@FreeBSD.orgOctober 20, 2007Kris Kennaway The FreeBSD Project kris@FreeBSD.orgIntroducing FreeBSD 7.0Introducing FreeBSD 7.0FreeBSD 7.0 will be the next release of FreeBSD, and the firstmajor release in 2 years.Due out some time later this year (currently in pre-release andavailable for testing)FreeBSD 7.0 brings major changes to the BSD and opensource operating system landscape.Outline:I The SMPng project: a 7 year journey“Symmetric Multi-Processor, next generation”II Major new features debuting in FreeBSD 7.0III What the future holds for FreeBSDKris Kennaway The FreeBSD Project kris@FreeBSD.orgIntroducing FreeBSD 7.0Part I: The SMPng project: A 7 year journey“Last week, approximately 20 BSD developers gottogether and discussed how to move FreeBSD’s SMPsupport to the next level. Our effort will be largely basedon the work that has been done in BSD/OS, whichshould make things go much more smoothly than theyotherwise might, but we still expect -current to bedestabilized for an extended period of time.”– Jason Evans, email to freebsd-current list, 19 June 2000Kris Kennaway The FreeBSD Project kris@FreeBSD.orgIntroducing FreeBSD 7.0Multiprocessor support, old and new: FreeBSD 4.xFreeBSD 4.x is a single-threaded kernel with limited multiprocessorsupport.Able to run user code on multiple processorsOnly one process at a time can execute in the kernel (“Giantlock” around entire kernel)Device interrupts may be processed in parallel, subject tosome constraintsThe historical BSD kernel architecture worked very well forsingle-processor systems. It fundamentally does not scale tomulti-processor systems, which are now becoming universal.Kris Kennaway The FreeBSD Project kris@FreeBSD.orgIntroducing FreeBSD 7.0Multiprocessor support, old and new: The SMPng projectGoal: Re-design the FreeBSD kernel as a multi-threaded system,for “next generation” SMP supportMultiple CPUs must be able to execute kernel code in parallelSerialization of shared data structures via various lockingprimitivesBalance the performance needs of Uni-Processor (UP) andSMP systems (not always different needs)A major challenge......now completeKris Kennaway The FreeBSD Project kris@FreeBSD.orgIntroducing FreeBSD 7.0SMPng and the Universal Development ModelThe SMPng project followed a simple 3 step process:Kris Kennaway The FreeBSD Project kris@FreeBSD.orgIntroducing FreeBSD 7.0SMPng, step 1: First, make it work; FreeBSD 5.xFreeBSD 5.0-5.2.1 (2003-01-17 - 2004-02-22)Debut of the new architectural model for symmetricmultiprocessor support in FreeBSD.FreeBSD 5.3 (2004-11-06), 5.4 (2005-05-09)The fundamental architectural changes were largely in placeSome initial progress with kernel parallelism by 5.3 and 5.4(network stack, virtual memory, ...)Kris Kennaway The FreeBSD Project kris@FreeBSD.orgIntroducing FreeBSD 7.0SMPng, step 2: Then make it work well; FreeBSD 6.xFreeBSD 6.0 (2005-11-01), 6.1 (2006-05-08), 6.2 (2007-01-15)Stabilized the work of the 5.x branchPerformance benefits from subsequent development worke.g. Virtual File System (VFS) and Unix File System (UFS)now allow parallel accessLarge parts of the kernel may now operate in parallel, withsignificant performance gains on many common workloadsKris Kennaway The FreeBSD Project kris@FreeBSD.orgIntroducing FreeBSD 7.0SMPng, step 3: Then make it fast; FreeBSD 7.0The goals of the SMPng project have been achievedThe FreeBSD 7 kernel is a fully parallel systemThe “Giant lock” is no longer present on almost all possibleworkloadsMajor shift of focus from correctness to optimization, withimpressive resultsKris Kennaway The FreeBSD Project kris@FreeBSD.orgIntroducing FreeBSD 7.0A case study: SQL database performance“Online transaction processing” benchmark;/usr/ports/benchmarks/sysbenchComplex transaction-based queriesRead-only: no disk access to avoid benchmarking diskperformanceClients and servers on the same systemPostgreSQL 8.2.4 (process-based + System 5 Inter-ProcessCommunication (IPC)MySQL 5.0.45 (thread-based)Test hardware:1. 4 * 2-core Opteron (amd64 mode)2.2GHz CPUs, 4 GB RAM2. 2 * 4-core Xeon E5320 (i386 mode)1.8GHz CPUs, 3.5GB RAMKris Kennaway The FreeBSD Project kris@FreeBSD.orgIntroducing FreeBSD 7.0