On 9/12/05, Reuben Martin <reuben.m@xxxxxxxxx> wrote: > On 9/12/05, Eric Dantan Rzewnicki <rzewnickie@xxxxxxx> wrote: > > On Thu, Sep 08, 2005 at 08:38:02PM -0500, Reuben Martin wrote: > > > On 9/7/05, guy <sayhi2guy@xxxxxxxxxxxxx> wrote: > > > > Hi > > > > I'm just about to compile a 2.6.13 kernel for low latency audio work. > > > > The docs I have accessed are either confusing (sorry if its just me ;0) > > > > ) or rendered out of date by kernel developments. > > > > I know that some features such as pre-empt are now in the kernel. Which > > > > patches (if any) would you folks advise that I should apply. I am also > > > > unsure if should enable the 'big kernel lock' feature. > > > > Thanks in advance for any help > > > realtime-preempt patches are the latest and greatest for latency > > > improvements. They are very actively maintained by Ingo Molnar, same > > > guy who created the preempt patches for the 2.4 kernel series. > > > > For historical clarification ( and someone correct me if I'm wrong on > > any of this ), Ingo did a set of low latency patches for 2.2/2.4 that > > basically showed that breaking up long code pathes could improve linux's > > latency performance. These were proof of concept patches, in a sense, > > but not accepted, nor intended, for the mainline kernel. > > > > Andrew Morton created a smaller and more tightly focused set of > > long-code-path-splitting low-latency patches for 2.4 inspired by Ingo's > > earlier work. These were intended to find an approach to achieving > > low-latency more acceptable to the kernel devs. > > > > Robert Love created a set of Preemption patches for 2.4 that were > > commonly applied along with Andrew's LL patches. The preemption patches > > were a different approach to achieve low-latency which allowed code > > paths which might run for a long time to be marked as pre-emptible. > > > > I know all three of them contributed. I'm not sure who's was merged > into 2.5. I remember I used to use a combination of two diffferent > latency patch sets. > > > > Much of Andrew and Robert's work on 2.4 was incorporated into the 2.5 > > development kernel and thus the 2.6 series. However there were still > > latency problems with 2.6, so Ingo has again taken the lead in producing > > the current series of realtime-preemption patches. A lot of this work is > > now present in the mainline 2.6.13.x kernel. > > If I understand correctly, chunks of his patch are slowly absorbed > into the mainline a bit at a time while he continues to keep finding > ways to shorten the length of code paths. >
