I am investigating some locking scheme using semaphores. To evaluate basic system speed I run a loop of getting some semaphore info and display it:
while : ; do ./semshow; done > res.txt
I ran this on 3 boxes - two similar modern HP XEON boxes, one running SCO OpenServer 5, the other is Fedora 2.6.9, and one old PIII box under modern Linux (have no info).
The results are very counter intuitive: H/W | OS | avg number of runs ber sec ---- | --- | ------------------------- XEON | SCO | 1700 XEON | Fedora | 500 PIII | Linux (recent distro, unknown) | 900
All three systems were pretty much idle at the test run time.
I would like to ask, what would be the factors that makes ancient Unix to outperform modern OSes, also, how come PIII box outperform modern XEON box under similar OS. Any ponters would be appreciated.
The semshow program is very basic, see listing below:
semlib.h has these defs:
Hello,
I have a Supermicro server with a P4SCI mother board running Debian Sarge 3.1. This is the "dmidecode" output related to RAM info:
RAM speed information is incomplete.. "Current Speed: Unknown", is there anyway/soft to get the speed of installed RAM modules? thanks!!
Regards :)... (0 Replies)
Hi,
I am looking to use a semaphore for the first time in one of my scripts. I am just wondering if there are any simple examples or tutorials around?
I am a beginner so the simpler the better :)
Thanks
-Jaken (2 Replies)
I analysed disk performance with blktrace and get some data:
read:
8,3 4 2141 2.882115217 3342 Q R 195732187 + 32
8,3 4 2142 2.882116411 3342 G R 195732187 + 32
8,3 4 2144 2.882117647 3342 I R 195732187 + 32
8,3 4 2145 ... (1 Reply)
Control two exclusively shared resources(semaphore). The two resources are two files. The producer will write even numbers to one file, and odd numbers to another one. The consumer respectively reads from each file until it gets 5 even numbers and 5 odd numbers.
Can any one help me with the... (0 Replies)
If I create a semaphore and then I fork a number of child processes then all the child process use that same semaphore.
Since the process address spaces are different rfom each other then how all the child process are able to access the same semaphore?
I understand that semaphore/mutex is at os... (0 Replies)
I was asked to add this piece of code to a c program which I will execute through the shell:
for(long i = 0; i < NITER; i++)
{ sem_wait( &sema);
count++;
sem_post( &sema); }
I didn't get it, which is the critical section ? if it's "count++" how would a thread wake up in order to enter it... (1 Reply)