That iterates MAXN which must be at least 50847534 - for each of the three calls to time_loop() the function ptr is jumping to the same function. Unless that code has to dynamically allocate memory or there is OS contention for some resource, there ought not be those differences.
I happen not to like the static declaration of functions for a variety of reasons except in certain instances-- But that is very probably not the cause of this problem.
You need to call getrusage() before and after - like you now do with clock() to see what is happening in the world of system resources.
Also clock() is just wall time, use the times() function to get system & user time - as consumed by parent & child.
I think shamrock wants to see that you are not calling exec or something else that eats the system resources or causes high kernel times maybe.
having problems using scp in that during peak hours it appears to time out.
anyone have similar experiences? any thoughts regarding a solution... (1 Reply)
I need to make it so an autmated process which involves ssh, times out if ssh prompts for a password. Most of the time it shouldnt prompt for a password. But if it does i need it to time it out or get a status and stop the ssh and log that the ssh failed and move onto the next server. Is there any... (9 Replies)
hi everyone. If you have a function created in your code and you want to find out how long it takes for it to run you can use a struct called gettimeofday().
so lets say we have a function like this
int myfunction (int r)
{
/*some math calculations*/
return answer;
}
How do i set up... (3 Replies)
Hello there, I just needed to know how to get the timing right when using the gcc __builtin_prefetch() function, that is, how many instructions before the actual utilization of the data should I make the prefetch call.
I will be measuring the L1 cache hit rate with valgrind's cachegrind,... (3 Replies)
I'm attempting to read a file that is composed of complex 32-bit floating point values on Solaris 10 that came from a 64-bit Red Hat computer.
When I first tried reading the file, it looked like there was a byte-swapping problem and after running the od command on the file Solaris and Red Hat... (2 Replies)
Hello ,
When using vim, can ctag and cscope support recording search results and displaying the history results ? Once I jump to one tag, I can use :tnext to jump to next tag, but how can I display the preview search result? (0 Replies)
i have a very big script i have that i'd like to add a timeout to.
this script runs on a several remote host. i update this script with timeout clause and then copy it over to all the hosts on which it is currently on.
basically, i want the timeout to make the script abort/exit if it's... (1 Reply)
I have two shell scripts, one written with xargs for parallel processing (p1) and the other written in old school way (p3) .
when I execute them, i get the below values.
$ time ./p1
real 0m25.36s
user 0m0.32s
sys 0m0.80s
$ time ./p3
real 0m23.25s
user 0m6.20s
sys ... (4 Replies)
-> We have 2 servers server1 and server2 server.
->server1 is master application and server2 is slave application server. ->output of server1 hardware and slave timing:
# hwclock --show Thu 05 Jun 2014 05:34:08 PM SGT -0.465666 seconds # date Thu Jun 5 17:34:16 SGT 2014
# cd... (6 Replies)
Hello and thanks in advance for any help anyone can offer me
I'm trying to learn the find command and thought I was understanding it... Apparently I was wrong. I was doing compound searches and I started getting weird results with the -size test. I was trying to do a search on a 1G file owned by... (14 Replies)
Discussion started by: bodisha
14 Replies
LEARN ABOUT REDHAT
fb.modes
fb.modes(8) Linux frame buffer utils fb.modes(8)NAME
fb.modes - frame buffer modes file
DESCRIPTION
/etc/fb.modes contains an unlimited number of video mode descriptions. The general format of a video mode is:
mode
geometry <xres> <yres> <vxres> <vyres> <depth>
timings <pixclock> <left> <right> <upper> <lower> <hslen> <vslen>
options <value>
endmode
OPTIONS
geometry options:
xres visible horizontal resolution (in pixels)
yres visible vertical resolution (in pixels)
vxres virtual horizontal resolution (in pixels)
vyres virtual vertical resolution (in pixels)
depth display depth (in bits per pixel)
timing options:
pixclock
length of one pixel (in picoseconds)
left left margin (in pixels)
right right margin (in pixels)
upper upper margin (in pixel lines)
lower lower margin (in pixel lines)
hslen horizontal sync length (in pixels)
vslen vertical sync length (in pixel lines)
other options:
the first value of this options is the default
hsync {low|high}
the horizontal sync polarity
vsync {low|high}
the vertical sync polarity
csync {low|high}
the composite sync polarity
extsync {false|true}
enable or disable external resync. If enabled the sync timings are not generated by the frame buffer device and must be pro-
vided externally instead. Note that this option may not be supported by every frame buffer device
laced {false|true}
enable or disable interlace. If enabled the display will be split in two frames, each frame contains only even and odd lines
respectively. These two frames will be displayed alternating, this way twice the lines can be displayed and the vertical fre-
quency for monitor stays the same, but the visible vertical frequency gets halved
double {false|true}
enable or disable doublescan. If enabled every line will be displayed twice and this way the horizontal frequency can easily
be doubled, so that the same resolution can be displayed on different monitors, even if the horizontal frequency specifica-
tion differs. Note that this option may not be supported by every frame buffer device
INTERNALS
Generally a frame buffer display is organized as follows:
+---+---------------+---+---+
| | ^ | | |
| | | 5 | | |
| | v | | |
+---#################---+---+
| # ^ # | |
| # | # | |
| # | # | |
| 1 # | 2 # 3 | 4 |
|<->#<------+------>#<->|<->|
| # | # | |
| # | 6 # | |
| # | # | |
| # v # | |
+---#################---+---+
| | ^ | | |
| | | 7 | | |
| | v | | |
+---+---------------+---+---+
| | ^ | | |
| | | 8 | | |
| | v | | |
+---+---------------+---+---+
1 left margin
2 xres
3 right margin
4 horizontal sync len
5 upper margin
6 yres
7 lower margin
8 vertical sync len
The area bordered with `#' is the visible display area. Horizontal and vertical frequencies can now easily be calculated, for this the sum
of horizontal or vertical values are important
htotal = left + xres + right + hslen
vtotal = upper + yres + lower + vslen
The length of one line can now be calculated with pixclock
line = pixclock * htotal
and we have the horizontal frequency
hfreq = 1E12 / line = 1E12 / (pixclock * htotal)
To get the vertical frequency vtotal must eventually adjusted. If the display is laced, vtotal must be halved or if the display is a dou-
blescan one, vtotal must be doubled. Now we can calculate the length of one frame
if (lace) vtotal /= 2
if (double) vtotal *= 2
frame = vtotal * line
and we get also the vertical frequency
vfreq = 1E12 / frame = hfreq / vtotal
SEE ALSO fbset(8), fbdev(4)local Aug 1996 fb.modes(8)