Date: Fri, 20 May 2005 18:08:45 -0500 From: Dan Nelson <dnelson@allantgroup.com> To: alexander <arundel@h3c.de> Cc: freebsd-hackers@freebsd.org Subject: Re: Looking for ANSI/VT100 code replacement. Message-ID: <20050520230845.GC51092@dan.emsphone.com> In-Reply-To: <20050520224726.GA7951@skatecity> References: <20050520224726.GA7951@skatecity>
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In the last episode (May 21), alexander said: > I'd like to port an application that was written in x86 assembly for > Linux. So far all I had to do is change the Linux calling convention > (registers) to Posix style (stack). > > However at one point this application outputs 5 characters to stdout > (using syscall write and fd=1). These 5 characters however are then > being deleted and overwritten again. The application uses VT100 codes > to do this. > > First it moves the cursor to the left 5 times then it deletes > everything from the end of the line to the current cursor position. > > However this slows down the whole application. That's why I'd like to > replace that code with something faster. How often are you doing this? I wrote a quick microbenchmark and my pIII-900 box can do 80000 writes() per second of "\e[5D\e[Kabcde". I don't think that's your bottleneck. If it is, the usual solution is to not do a write on every iteration. You've got a (maximum) 100hz screen refresh rate anyhow, so doing more than 100 updates per second won't do you any good. Even 10 is probably more than you need. -- Dan Nelson dnelson@allantgroup.com
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