Originally posted by: dimir

I need to create a C program to get network interface statistics (e. g. in/out packets/bytes/errors). I used examples of using libperfstat here:

http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.prftools/doc/prftools/prftools07.htm

It works well but for some reason the results I get totally differ from what entstat command shows. And it happens on 2 different machines (5.3 and 6.1). Does anybody know why is the difference and should I make any adjustments to my program in order to get proper results?

Below are details on the subject.

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1. My program code #

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$ cat perfstat-net.c
#include <stdio.h>
#include <stdlib.h>
#include <libperfstat.h>
#include <string.h>

int main(int argc, char *argv[])
{
perfstat_netinterface_t ps_if;
perfstat_id_t ps_id;

if (argc != 2) {
fprintf(stderr, "usage: %s <device>\n", argv[0]);
exit(EXIT_FAILURE);
}

strcpy(ps_id.name, argv[1]);

if (perfstat_netinterface(&ps_id, &ps_if, sizeof(perfstat_netinterface_t), 1) != 1) {
fprintf(stderr, "perfstat_netinterface() failed\n");
exit(EXIT_FAILURE);
}

printf("Statistics for interface : %s\n", ps_if.name);
printf("------------------------\n");
printf("\ninput statistics:\n");
printf("number of packets : %llu\n", ps_if.ipackets);
printf("number of bytes : %llu\n", ps_if.ibytes);
printf("number of errors : %llu\n", ps_if.ierrors);
printf("\noutput statistics:\n");
printf("number of packets : %llu\n", ps_if.opackets);
printf("number of bytes : %llu\n", ps_if.obytes);
printf("number of errors : %llu\n", ps_if.oerrors);

exit(EXIT_SUCCESS);
}

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1. My program output #

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$ gcc -o perfstat-net perfstat-net.c -lperfstat -Wall && ./perfstat-net en1
Statistics for interface : en1

---

input statistics:
number of packets : 508180206 <--- in packets
number of bytes : 3914575317 <--- in bytes
number of errors : 0 <--- in errors

output statistics:
number of packets : 899241 <--- out packets
number of bytes : 66302139 <--- out bytes
number of errors : 0 <--- out errors

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1. entstat output #

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$ entstat en1

---

ETHERNET STATISTICS (en1) :
Device Type: Host Ethernet Adapter (l-hea)
Hardware Address: 00:1a:64:f0:3a:31
Elapsed Time: 25 days 22 hours 24 minutes 24 seconds

Transmit Statistics: Receive Statistics:

---

---

Packets: 183463 Packets: 49625506 <--- out/in packets
Bytes: 13869163 Bytes: 4238405514 <--- out/in bytes
Interrupts: 0 Interrupts: 49147441
Transmit Errors: 1498 Receive Errors: 0 <--- out/in errors
http://...

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1. OS version #

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$ oslevel -s
6100-01-01-0823
#AIX-Forum

Originally posted by: SystemAdmin

entstat gives statistics for ethernet device driver and device. For comparison with perfstat network interface statistics, you should use netstat with option -i or -I <interface>.
#AIX-Forum

Originally posted by: dimir

Thank you for the answer, indeed with

netstat -D -I en1

I get the same results as perftat API returns. So, you mean, entstat gives ethernet device driver statistics (software level) while perfstat gives statistics of the device itself (hardware level)?
#AIX-Forum