Re: Excessive CPU usage with MinGW

[Rik]

On 11/21/2013 03:27 PM, Michael Goffioul wrote:

On Thu, Nov 21, 2013 at 5:03 PM, Rik <address@hidden> wrote:

11/22/13

When running the octave GUI on Windows XP I'm seeing nearly 100% CPU usage
when the GUI is idle.  Looking in the task manager I see about 2/3 of the
CPU consumed by csrss.exe and 1/3 by octave-gui.exe.  According to
Wikipedia the csrss.exe stands for Client/Server Runtime Subsystem and is
involved when console or thread activity is used.  Is anyone else seeing this?

Is it single or multi-core. I also have excessive CPU usage, though it only affects one core (I've a Atom N470 with 2 (pseudo) cores).

Single core, so at least the behavior is consistent.

For the record, as John mentions it, I suspect the problem lies in readline event-hook loop. Normally, readline "select" on stdin with a 100ms timeout. After the timeout, it executes the input-hook, then starts all over again. In Win32, you can't "select" in stdin, so there's nothing to throttle the readline loop.

I used to work around the issue in the previous octave binaries, by patching readline and use another approach for reading characters with a timeout. Though I didn't port it to MXE. I was hoping the problem would have been solved in the meantime (my patch was based on readline-5 and MXE is using readline-6.2).

I intend to have a look at this issue in the coming days. Namely, the GnuWin32 readline version has worked around the issue, using an approach that is similar to mine.

Excellent.  It certainly doesn't stop me from using Octave on Windows, but it isn't a great selling point either.

--Rik