Date: Tue, 27 Aug 2013 12:02:21 +0200 From: Zbyszek Bodek <zbb@semihalf.com> To: fabiodive <fabiodive@gmail.com> Cc: freebsd-arm@FreeBSD.org Subject: Re: HEADS UP: Superpages support for ARMv6/v7 Message-ID: <521C792D.1030704@semihalf.com> In-Reply-To: <3635F96E-6C83-4310-AE6B-DE2F2EA09C4C@gmail.com> References: <521BA6F6.3010308@semihalf.com> <0093E5B7-EC77-40AB-8AD4-0778E42993A6@gmail.com> <521C74A3.4050207@semihalf.com> <3635F96E-6C83-4310-AE6B-DE2F2EA09C4C@gmail.com>
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On 27.08.2013 11:45, fabiodive wrote: > OK, that's fine, should be fine also having some configuration > "option" into the kernel configuration file… > thank you again > f. Hello again. Well, in general on i386/amd64 this feature is enabled by default. It would be reasonable to enable SP by default on ARM too after longer tests and evaluation on various ARM-based chips. But you are right, it would be convenient to enable this in kernel configuration especially on ARM. I will discuss this with Developers. Best regards > > > On Aug 27, 2013, at 10:42 AM, Zbyszek Bodek <zbb@semihalf.com> wrote: > >> On 27.08.2013 11:36, fabiodive wrote: >>> Hello, >>> I am going to do some tests on my beagle bone black here, >>> please could you give me an hint about enabling the feature >>> into the kernel? Which directive should I use? >>> thank you >>> f. >>> >> >> Hello. >> >> If you are not using loader then open: >> sys/arm/arm/pmap-v6.c >> and set "sp_enabled = 0;" -> "sp_enabled = 1;" >> recompile. >> >> OR if using loader then set: >> vm.pmap.sp_enabled=1 in loader.conf >> >> Both methods are sufficient. >> >> Best regards >> Zbigniew Bodek >> >> >>> On Aug 26, 2013, at 8:05 PM, Zbyszek Bodek <zbb@semihalf.com> wrote: >>> >>>> Hello Everyone. >>>> >>>> I'm happy to announce that Superpages support for ARM has just been >>>> integrated to the FreeBSD HEAD: >>>> http://svnweb.freebsd.org/changeset/base/254918 >>>> >>>> This project was sponsored by The FreeBSD Foundation and Semihalf. >>>> It was developed with great support of Alan Cox (alc) who was also the >>>> technical reviewer of the code. Thank you very much Alan for all your help! >>>> I would also like to thank Grzegorz Bernacki (gber) and Rafal Jaworowski >>>> (raj) for mentoring and help with the code integration and all the >>>> people involved in testing of the patches and review. >>>> >>>> The code was tested on a quad-core, ARMv7, Marvell Armada XP SoC in SMP >>>> environment. >>>> >>>> Superpages is a feature that can increase TLB coverage and allow for >>>> efficient use of page table entries. Current implementation for ARM >>>> supports two page sizes: 4KB small pages (used as base pages) and 1MB >>>> sections (used as superpages). >>>> Superpages are created either directly by 1MB section insertion or as a >>>> result of promotion of 256 4KB pages. In both cases superpages creation >>>> and utilization depends on *sp_enabled* sysctl variable. >>>> >>>> By default, superpages support is disabled. >>>> In order to use this functionality one needs to set >>>> *vm.pmap.sp_enabled* tunable to non-zero value. This can be done either >>>> in loader.conf or by modifying *sp_enabled* variable in >>>> sys/arm/arm/pmap-v6.c . Statistics regarding superpages usage are >>>> available through: sysctl vm.pmap.section >>>> >>>> All ARMv6/v7-based platforms can take advantage from superpages, so >>>> please enable this feature on your ARM kernels. >>>> We will appreciate all your feedback regarding performance impact and >>>> general system behavior. >>>> >>>> Performance improvement should be visible in all tasks where intensive >>>> memory utilization is involved. GUPS (Giga Updates Per Second) benchmark >>>> can be used to show the difference in memory utilization efficiency with >>>> superpages enabled and disabled. GUPS src can be downloaded from here: >>>> http://people.freebsd.org/~raj/patches/arm/superpages/GUPS.tar.gz >>>> >>>> Exemplary GUPS results: >>>> -------------------------------------------------------------------- >>>> *superpages enabled* >>>> vm.pmap.section.promotions: 1024 >>>> vm.pmap.section.p_failures: 58 >>>> vm.pmap.section.mappings: 0 >>>> vm.pmap.section.demotions: 0 >>>> >>>> # ./gups >>>> Main table size = 2^27 = 134217728 words >>>> Number of updates = 536870912 >>>> CPU time used = 97.085938 seconds >>>> Real time used = 97.082504 seconds >>>> 0.005530048 Billion(10^9) Updates per second [GUP/s] >>>> >>>> vm.pmap.section.promotions: 2048 >>>> vm.pmap.section.p_failures: 58 >>>> vm.pmap.section.mappings: 0 >>>> vm.pmap.section.demotions: 0 >>>> >>>> * superpages disabled * >>>> Main table size = 2^27 = 134217728 words >>>> Number of updates = 536870912 >>>> CPU time used = 145.679688 seconds >>>> Real time used = 145.680798 seconds >>>> 0.003685255 Billion(10^9) Updates per second [GUP/s] >>>> -------------------------------------------------------------------- >>>> >>>> *Self host buildworld* >>>> World build time on Armada XP has shortened from 6h 36min to >>>> 5h 14min with superpages enabled. >>>> >>>> *Stress tests* >>>> stress --cpu 4 --io 4 --vm 2 --vm-bytes 800M >>>> Survived long time runs, large superpages creation ratio has been observed. >>>> >>>> *Swapping* >>>> No problems with swapping or system running under heavy load with >>>> shortage of memory have been observed. >>>> >>>> >>>> Please feel free to send your results. >>>> >>>> Best regards >>>> Zbigniew Bodek >>>> _______________________________________________ >>>> freebsd-arm@freebsd.org mailing list >>>> http://lists.freebsd.org/mailman/listinfo/freebsd-arm >>>> To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org" >>> >> >
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