Re: [Boost-users] substantial lag time difference from boost::thread 1.57 and 1.60

Subject: Re: [Boost-users] substantial lag time difference from boost::thread 1.57 and 1.60
From: Michael Powell (mwpowellhtx_at_[hidden])
Date: 2016-07-08 16:42:33

On Fri, Jul 8, 2016 at 2:35 PM, David Medine <dmedine_at_[hidden]> wrote:
> Hello,
> I am an engineer in a neurosciences lab. We have some data acquisition
> software that uses boost::thread and some other boost libraries as well.
> Part of my job is to measure the lag time for our devices' data acquisition.
> I have been testing the acquisition software when linking against boost
> v.1.57.0 and v.160.0.

10 ms is pretty good on a non-r/t OS such as Windows, much less
Windows 7 (basically, Vista core). You're sure you're building against
release and not debug mode?

> Basically I generate a test signal and read it in with an NIDAQ and our EEG
> system. The signal is a series of 3ms long pulses. When the input to the
> NIDAQ goes high, I generate a timestamped marker. Meanwhile the EEG system
> is getting the same pulse train input and I record that digital data on its
> own thread and timestamp that as well. Then I compare the timestamps at
> which the EEG signal has a rising edge with the timestamps of the markers.
> The difference between these time values is the lag of the EEG system.
>
> The app I use to get the EEG signal uses boost::thread. The lag time is
> consistently ~2.7 ms when linking against boost v.1.57.0 and is a whopping
> 11.6 ms when I link against v.1.60.0. Since the data acquisition happens in
> a tight loop on its own thread, I am guessing that there is some kind of
> increased latency of boost threads in newer versions of the library.
>
> Does anybody know what might be causing this? I am on Windows 7, 64-bit and
> am using the pre-compiled boost libraries (i.e. I am not compiling them
> myself).
>
> Cheers,
> David
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users