On Mon, 17 Jan 2011 21:05:11 +0200
Alexander Nezhinsky <alexandern@xxxxxxxxxxxx> wrote:
> +static void work_timer_evt_handler(int fd, int events, void *data)
> +{
> + unsigned long long n; /* timer expirations */
> + int ret;
> +
> + ret = read(timer_fd_rd, &n, sizeof(n));
> + if (ret < 0) {
> + if (ret == -EAGAIN)
> + return;
> + eprintf("Failed to read from pipe, %m\n");
> + return;
> + }
> + current_time += n * WORK_TIMER_INT_MSEC;
Hmm, I think that you need gettimeofday for this signal
approach. Signals could be lost (the process could miss a signal when
it's too busy) so the above code doesn't work.
timerfd is nice because reading the file descriptor tells how many
times the timer expires.
As I wrote, I don't want to add gettimeofday for the timerfd approach
but using gettimeofday for this signal approach is fine by me.
One thing I want to change in your previous patch is using 'unsigned
int when' in tgt_work struct instead of struct timeval. It allows the
timerfd and signal appoaches to share that. The signal appoach can
convert struct timeval to unsigned int current_time.
Thanks,
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