On 2015-03-24 at 12:20:39 +0100, Vadim Kochan <vadi...@gmail.com> wrote:
> From: Vadim Kochan <vadi...@gmail.com>
>
> Trafgen uses all the online cpus even if number of packets specified
> by -n is less than numbers of selected cpus.
> Such behaviour leads to issues:
>
> - trafgen re-calculates number of packets per cpu which
> leads to rounding it to 0 then no packets will be sent.
>
> - trafgen might send more packets than specified by -n because
> of using all the online cpus.
Good catch!
> Fixed by calculation the minimum number of cpus for generation
> number of packets specified by -n.
>
> Signed-off-by: Vadim Kochan <vadi...@gmail.com>
> ---
> cpus.h | 7 +++++++
> trafgen.c | 3 +++
> 2 files changed, 10 insertions(+)
>
> diff --git a/cpus.h b/cpus.h
> index 0626726..be33884 100644
> --- a/cpus.h
> +++ b/cpus.h
> @@ -25,4 +25,11 @@ static inline unsigned int get_number_cpus_online(void)
> return ret;
> }
>
> +static inline unsigned int alloc_cpus_by_n_pkts(int npkts)
> +{
> + unsigned int cpus = get_number_cpus_online();
> +
> + return min_t(unsigned int, ((double)npkts / cpus) * cpus, cpus);
Why the divide & multiply? Wouldn't min_t(unsigned int, npkt, cpus) be
enough?
> +}
> +
> #endif /* CPUS_H */
> diff --git a/trafgen.c b/trafgen.c
> index 9151b5d..5403d47 100644
> --- a/trafgen.c
> +++ b/trafgen.c
> @@ -1038,6 +1038,9 @@ int main(int argc, char **argv)
> }
> }
>
> + if (ctx.num && ctx.num < ctx.cpus && ctx.cpus > 1)
> + ctx.cpus = alloc_cpus_by_n_pkts(ctx.num);
I'd rather just inline the min_t here instead of having an own function.
Maybe put a short comment outlining the two issue you mention in the
patch description.
Thanks a lot!
Tobias
> +
> if (argc < 5)
> help();
> if (ctx.device == NULL)
> --
> 2.3.1
>
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