From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1NtxE1-0001Kz-OF for garchives@archives.gentoo.org; Tue, 23 Mar 2010 06:04:25 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 5720AE0942 for ; Tue, 23 Mar 2010 06:04:25 +0000 (UTC) Received: from mail-yw0-f182.google.com (mail-yw0-f182.google.com [209.85.211.182]) by pigeon.gentoo.org (Postfix) with ESMTP id A62E8E08F7 for ; Tue, 23 Mar 2010 05:19:17 +0000 (UTC) Received: by ywh12 with SMTP id 12so3045354ywh.32 for ; Mon, 22 Mar 2010 22:19:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type :content-transfer-encoding; bh=kzvahVC9GwP1fnMzLqMCpNu3+D4r0swuU38JW/5QxTI=; b=sMzQkQwgjM0ERNA0D6hovU1so3ody2fYbEA8LdnneU93lTGjVMV3x5ubgQPzHZf4kI CvCoSUhejwecnTsJZzuSUv+BHBLmcJ+N5tDdhgHOhWaU6oTVzxIMYfcVgPYY+XbhOhZT m4OUriwrDcG2CAxtacNNv9hwK8/LowivWp2ao= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; b=IoSMtPXmI0hQVlfdQD60IEo5qfjrOkp4nZ+Jq2GDGPFeiPlw26zv/36GR4UISkXS+i erKpfXhtx1LSSTcPNXNZGAJ336geHVFJz53DtWL0uVkEe8Clo+6wUIyMJYUn++Qys6J4 frldHLkwoRWcacbTP4PMOSxG19gNuJ0bGBO7A= Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-embedded@lists.gentoo.org Reply-to: gentoo-embedded@lists.gentoo.org MIME-Version: 1.0 Received: by 10.90.37.14 with SMTP id k14mr5306729agk.53.1269321557190; Mon, 22 Mar 2010 22:19:17 -0700 (PDT) In-Reply-To: <20100320150237.2ee70a4e@osage.osagesoftware.com> References: <20100314102459.20d7883b@osage.osagesoftware.com> <20100315133434.GA15613@xyzzy.org.uk> <91FA647A1A781F41BBB0359765C90C15F713C8@mailsvr.orion-sys.com> <20100320150237.2ee70a4e@osage.osagesoftware.com> Date: Mon, 22 Mar 2010 22:19:17 -0700 Message-ID: Subject: Re: [gentoo-embedded] SOLUTION (partial) was: High Speed Serial Problem From: James Ausmus To: gentoo-embedded@lists.gentoo.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Archives-Salt: fd8f4687-ec07-4c68-9284-1f9ddb507199 X-Archives-Hash: b01b1ed53836c124921e9109a0aae501 On Sat, Mar 20, 2010 at 12:02 PM, David Relson w= rote: > Even with a dedicated thread, the program is still receiving multiple > characters per read. =A0Calculating average and maximum byte counts for > each 10,000 reads, I've often seen maximums of 150 and have never seen > an average under 12. =A0These numbers occur with VMIN=3D1 and VTIME=3D0. > > Is there a setting so that the serial port driver will release > characters sooner (rather than later)? Wasn't involved in the other thread, so my apologies if this has already been answered/stated, but are you using the realtime kernel patches? If you run RT-Preempt, then you can set the priority of the kernel thread that is handling the serial interrupt high than all the other kernel threads, which should improve your latencies... See https://rt.wiki.kernel.org/index.php/Main_Page for more info. HTH- James > Regards, > > David > >