Fixes the calculation of the mean absolute deviation (mdev) of the roundtrip times. mdev was previously calculated by computing the difference of maximum and minimum round trip times.
The calculation is now done using the same formula as in the iputils ping program.
Signed-off-by: Daniel Seither post@tiwoc.de --- Index: Makefile =================================================================== --- Makefile (revision 1659) +++ Makefile (working copy) @@ -28,7 +28,7 @@ CC = gcc CFLAGS += -pedantic -Wall -W -g3 -std=gnu99 -Os -fno-strict-aliasing EXTRA_CFLAGS = -DREVISION_VERSION=$(REVISION_VERSION) -LDFLAGS += +LDFLAGS += -lm
SBINDIR = $(INSTALL_PREFIX)/usr/sbin
Index: ping.c =================================================================== --- ping.c (revision 1659) +++ ping.c (working copy) @@ -29,6 +29,7 @@ #include <signal.h> #include <fcntl.h> #include <string.h> +#include <math.h>
#include "main.h" #include "ping.h" @@ -76,7 +77,7 @@ unsigned int seq_counter = 0, packets_out = 0, packets_in = 0, packets_loss; char *dst_string, *mac_string, *rr_string; double time_delta; - float min = 0.0, max = 0.0, avg = 0.0; + float min = 0.0, max = 0.0, avg = 0.0, mdev = 0.0; uint8_t last_rr_cur = 0, last_rr[BAT_RR_LEN][ETH_ALEN]; size_t packet_len;
@@ -260,6 +261,7 @@ if (time_delta > max) max = time_delta; avg += time_delta; + mdev += time_delta * time_delta; packets_in++; break; case DESTINATION_UNREACHABLE: @@ -289,11 +291,24 @@ else packets_loss = ((packets_out - packets_in) * 100) / packets_out;
+ if (packets_in) { + avg /= packets_in; + mdev /= packets_in; + mdev = mdev - avg * avg; + if (mdev > 0.0) + mdev = sqrt(mdev); + else + mdev = 0.0; + } else { + avg = 0.0; + mdev = 0.0; + } + printf("--- %s ping statistics ---\n", dst_string); printf("%u packets transmitted, %u received, %u%% packet loss\n", packets_out, packets_in, packets_loss); printf("rtt min/avg/max/mdev = %.3f/%.3f/%.3f/%.3f ms\n", - min, (packets_in ? (avg / packets_in) : 0.000), max, (max - min)); + min, avg, max, mdev);
ret = EXIT_SUCCESS;