From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4D4A9654.80402@domain.hid> Date: Thu, 03 Feb 2011 12:49:40 +0100 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <4D4A84ED.7030604@domain.hid> <4D4A8BD8.1060900@domain.hid> <4D4A9052.2090508@domain.hid> <4D4A9118.2070602@domain.hid> <4D4A957B.6050907@domain.hid> In-Reply-To: <4D4A957B.6050907@domain.hid> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] RT OS Selection advice for parallel processing List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: "xenomai@xenomai.org" Jan Kiszka wrote: > On 2011-02-03 12:27, Gilles Chanteperdrix wrote: >> Jan Kiszka wrote: >>> On 2011-02-03 12:04, Gilles Chanteperdrix wrote: >>>> Jan Kiszka wrote: >>>>> [ And, personally, I don't trust the NVIDIA driver a lot. But that might >>>>> be influenced by the fact that latest versions lock up my notebook >>>>> regularly after resume and that I filed another obvious locking issue of >>>>> the compilable driver stub around mmap_sem without any response from the >>>>> vendor. ] >>>> Some colleague of mine is using the NVIDIA driver (through the opengl >>>> mapping, not CUDA/VDPAU, whatever) on high-end NVIDIA boards in a non RT >>>> situation. he definitely observed some huge latencies not due to >>>> scheduling issues, when uploading textures to the GPU. We are talking >>>> tens of milliseconds here. >>> Ugh, tens of milliseconds is heavy, more than I would expect from >>> wbinvd. OTOH, uploading textures may involve mapping the RAM that >>> contains them for the GPU. To exclude that as source, he could try >>> instrumenting CACHE_FLUSH() (in nv-linux.h). >> No, it really looks like a bug in the blob. Of course the 40ms is a spot >> from time to time, usually, the upload is really fast. > > Unless it's a stall on the PCI bus, the blob should leaves some traces > in ftrace. I am talking about the kernel-space blob. ftrance does just show that the ioctl has been submitted. -- Gilles.