Date: Fri, 4 Dec 1998 09:04:38 -0600 (CST) From: Kevin Day <toasty@home.dragondata.com> To: luigi@labinfo.iet.unipi.it (Luigi Rizzo) Cc: hackers@FreeBSD.ORG Subject: Re: Nonblocking page fetching Message-ID: <199812041504.JAA04986@home.dragondata.com> In-Reply-To: <199812041248.NAA08298@labinfo.iet.unipi.it> from Luigi Rizzo at "Dec 4, 1998 1:48:36 pm"
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> > I have an application where I'm streaming large amounts of data from disk, > ... > > The hack I ended up using was another process that I could tell that I > > needed the frames, and all it did was sit in a for loop touching every page, > > to force them to be brought in. > > > > This has some obvious disadvantages, but it stopped my movie player from > > sitting in vmwait when it could be doing other things. > > is it so bad ? The forked process should consume very little memory > and because they are local you can even resort to or some cheap > local IPC mechanism to synchronize them. From a portability point of > view i think this is going to be to be better than provide a > specialised syscall. Well, I may be wrong, but I assumed that the CPU involved in just having a kernel bring pages in on it's own would be less. Is there anything that could be saved by putting this in the kernel? > > > One final note... Does anyone know what effect turning off the bzero on new > > pages would be? Security is not an issue in this system, as it's not > > again how bad is it ? bzero is generally done in the idle loop if i am > not mistaken so you should not be affected too badly by that unless you > are at or near 100% CPU usage. > We are at 100% cpu constantly. When I'm not drawing, i'm prerendering frames as far ahead as I can, as well as dealing with picky hardware that must be polled. Kevin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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