rigtorp / ipc-bench Goto Github PK

the test is using blocking API(read/write)，what if using noblock？

On 32 bit ARM delta calculation shall be as this:

    delta = ((stop.tv_sec - start.tv_sec) * 1000000000LL +
             (stop.tv_nsec - start.tv_nsec));

and

    delta = (stop.tv_sec - start.tv_sec) * 1000000000LL +
            (stop.tv_usec - start.tv_usec) * 1000LL;

Otherwise the expression overflows, because long is 4 byte in size and by default literals are int.
It was like a time travel, negative latency 😃

http://manpages.ubuntu.com/manpages/wily/man2/process_vm_readv.2.html

can you please add some benchmarks for unix datagram sockets?

Please do you have any benchmark result to share?
And why not use shared memory as IPC? It should have the lowest latency.

The linker causes an error when it is called for shm.c

Error message:
cc -g -lrt shm.c -o shm
shm.c: In function ‘main’:
shm.c:96:9: warning: format ‘%lli’ expects argument of type ‘long long int’, but argument 2 has type ‘int64_t’ [-Wformat]
shm.c:96:9: warning: format ‘%lli’ expects argument of type ‘long long int’, but argument 3 has type ‘int64_t’ [-Wformat]
shm.c:96:9: warning: format ‘%lli’ expects argument of type ‘long long int’, but argument 4 has type ‘int64_t’ [-Wformat]
/tmp/ccsPjw4i.o: In function main': /home/ncoretti/ipc-bench/shm.c:56: undefined reference toclock_gettime'
/home/ncoretti/ipc-bench/shm.c:82: undefined reference to `clock_gettime'
collect2: ld returned 1 exit status
make: *** [shm] Error 1

Tested on:
Linux VIGEMDT11 3.0.0-16-generic #28-Ubuntu SMP Fri Jan 27 17:44:39 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

Steps to reproduce the error:

1. Clone the git repository
   git clone git://github.com/rigtorp/ipc-bench.git
2. Enter the ipc-bench folder
   cd ipc-bench
3. Call make all
   make all

I know that in issue #13 you stated that you have no results to share but please consider adding a section to the README showing some example results the next time you test this code. From my understanding these are tests run on Linux. This repository is starred more than 500 times so clearly there is some interest in this.

I always get 1us latency for small packets.

I've made a local hack to cast delta as double, and actual value is 1.6us on my machine.

Perhaps it's something to consider?

Target shm does not compile

% make
cc -g -Wall -O3    pipe_lat.c   -o pipe_lat
cc -g -Wall -O3    pipe_thr.c   -o pipe_thr
cc -g -Wall -O3    unix_lat.c   -o unix_lat
cc -g -Wall -O3    unix_thr.c   -o unix_thr
cc -g -Wall -O3    tcp_lat.c   -o tcp_lat
cc -g -Wall -O3    tcp_thr.c   -o tcp_thr
cc -g -Wall -O3    tcp_local_lat.c   -o tcp_local_lat
cc -g -Wall -O3    tcp_remote_lat.c   -o tcp_remote_lat
make: *** No rule to make target 'shm', needed by 'all'.  Stop.