Date: Tue, 13 Jun 2006 09:11:10 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-smp@freebsd.org Cc: "Chris H." <fbsd@1command.com> Subject: Re: Concluding the SMPng project Message-ID: <200606130911.10775.jhb@freebsd.org> In-Reply-To: <20060612141235.3f7woozpc4888ksc@webmail.1command.com> References: <20060606195938.GA6581@xor.obsecurity.org> <20060612141235.3f7woozpc4888ksc@webmail.1command.com>
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On Monday 12 June 2006 17:12, Chris H. wrote: > Quoting Kris Kennaway <kris@obsecurity.org>: >=20 > > Several of us have been discussing recently whether it is time to > > bring the SMPng project to a formal conclusion. > > > > According to the SMPng project webpage, > > > > "The end goal of the SMPng Project is to decompose the Giant lock > > into a number of smaller locks, resulting in reduced contention (and > > improved SMP performance)." > > > > Thanks to the hard work of many developers over the past ~6 years, this > > goal is now complete. > > > > While Giant has not been completely eliminated from the kernel and > > several subsystems are still giant-locked (notably ipv6, tty, and CAM, > > although work is in progress on all of these fronts), kernel profiling > > traces show that for many real-world application loads the Giant lock > > is simply no longer a factor in the performance of the SMP kernel. > > > > See e.g. > > > > http://www.bsdcan.org/2006/papers/FilesystemPerformance.pdf > > > > for one such measurement of the extent of Giant locking in FreeBSD > > 6.x; other real-world application workloads are similar. > > > > Some of the benefits of formally concluding the SMPng project are: > > > > * The focus of SMP development work has largely changed from "break up > > Giant everywhere" to "carefully measure the effects of the locking > > decisions that were made, and optimize for greater performance and > > scalability". This is a major milestone and should be announced to > > the world, perhaps under the banner of a new "FreeBSD Scalability > > Project". > > > > * For example, a number of us are looking very closely at the nascent > > FreeBSD port to the Sun Ultrasparc T1, which provides 32 virtual CPUs > > (4 threads on 8 CPU cores) on a single chip. Optimizing for the new > > generation of SMP hardware is going to be a major effort over the > > coming year. >=20 > Ahh, so the contributions made by the PIII & PIV CPU's were merely to > obtain access to the Sparc systems, and the PIII & PIV will be relegated > to the ubiquitous I386 scrap heap, as the future and ultimate goal of > FreeBSD is to be Sun Microsystems. Pitty, FreeBSD has always provided > such wide scalability. So easy to implement on so many architectures. > I wish I had known it's agenda years ago. As I would not have spent > so many years and so many dollars building *BSD based infrastructures. > Perhaps I've misunderstood this announcement. But if not; > good riddance. Umm, no. However, with multi-core becoming more fashionable, x86 systems are going to start having more and more CPUs as well, so FreeBSD needs to work on scaling up to more than say 4 CPUs. =2D-=20 John Baldwin <jhb@FreeBSD.org> =A0<>< =A0http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" =A0=3D =A0http://www.FreeBSD.org
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