Messages in this thread | | | From | Olaf Meyer <> | Date | Wed, 3 Mar 1999 00:34:36 -0500 (EST) | Subject | strange do_gettimeofday behavior |
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I am experiencing rather strange behavior with the do_gettimeofday routine on my intel based pc running 2.0.33. When I make to consecutive calls to the do_gettimeofday function the last timestamp is smaller than the previous taken timestamp!!
Here's a code snippet:
#define DIFF_USEC(low, hi) \ (1000000L * (hi.tv_sec - low.tv_sec) + (hi.tv_usec - low.tv_usec))
char buffer[ETH_HLEN+sizeof(short)]; struct timeval xmitStart, xmitEnd;
do_gettimeofday(&xmitStart);
memcpy(buffer, ðHdr, ETH_HLEN); memcpy(buffer+ETH_HLEN, &type, sizeof(short));
// this sends something over a network interface card wrt_transmit_buffer(dev, buffer, sizeof(buffer));
do_gettimeofday(&xmitEnd);
diff = DIFF_USEC(xmitStart, xmitEnd);
How can diff be negative? Please let me know if you have an explanation.
Thanks,
Olaf
P.S. please also e-mail me, since I'm not on the mailing list
-- Olaf Meyer | mailto://olafm@seas.upenn.edu | _~o Computer and Information Science | http://www.seas.upenn.edu/~olafm | _-\_<, University of Pennsylvania | | (*)/'(*) Philadelphia, PA 19104-6389, USA | PGP: finger -l olafm@seas.upenn.edu
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