Messages in this thread | | | Date | Thu, 30 Jan 2003 17:41:30 -0800 | From | george anzinger <> | Subject | Re: [RFC][PATCH] linux-2.4.21-pre4_tsc-lost-tick_A0 |
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john stultz wrote: > > On Thu, 2003-01-30 at 17:08, george anzinger wrote: > > john stultz wrote: > > > I'm already somewhat cautious that loops_per_jiffy isn't going to cut it > > > with this patch (I'm thinking fast_gettimeoffset_quotient would probably > > > be better). So please let me know if you find any issues with this > > > patch. > > > > I think you are wondering about the "/", as am I. Possibly > > a while loop, or, something like > > fast_gettimeoffset_quotient, but scaled to do jiffies > > instead of micro seconds. Still you SHOULD be doing this so > > seldom that one wonders if the "/" is all that bad. > > Yea, I'm assuming it would be rare enough that the div won't be too much > of a performance drop and would make the code more clear. Although if it > is a concern I'm not opposed to speeding it up. > > > Another thing, possibly not so easily fixed given the > > division between "arch" code and common code, but I would > > like to see jiffies updated in only ONE place. With this > > patch it is updated in .../kernel/timer.c AND in > > .../arch/kernel/time.c. In the high-res-timers patch I made > > the jiffies update an inline in an "arch" header file so I > > could have the best of both worlds, i.e. update from common > > code using arch resources (TSC, etc). > > Yea, I'm not psyched about that as well (not only is it updated twice, > but three times: arch independent, tsc and cyclone). The inline bit > sounds interesting, are you planning on pushing that in?
I am a bit discouraged on that front. I was hoping to get the POSIX clocks & timers patch in, but it is long past Halloween and, while he said he might, he didn't. I don't know if he is finished as yet, but... The jiffies update was part of the core patch to do the high res timers which he said he would not take. I would like to try parting it out and pushing in some stuff, such as scmath.h which makes things like fast_gettimeoffset_quotient not only understandable but easy. Folks in the cpu frequency area would like that. Still, my boss has other plans...
-- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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