-----Original Message-----
> Date: Thu, 29 Nov 2018 14:02:03 +0530
> From: "Bhagavatula, Pavan" <pavan.bhagavat...@cavium.com>
> To: "Jacob, Jerin" <jerin.jacobkollanukka...@cavium.com>
> CC: "dev@dpdk.org" <dev@dpdk.org>, "Bhagavatula, Pavan"
> <pavan.bhagavat...@cavium.com>
> Subject: [dpdk-dev] [PATCH] eal: roundup tsc frequency when estimating it
>
> When estimating tsc frequency using sleep/gettime round it up to the
> nearest multiple of 10Mhz for more accuracy.
>
> Signed-off-by: Pavan Nikhilesh <pbhagavat...@caviumnetworks.com>
> ---
> lib/librte_eal/common/eal_common_timer.c | 4 ++--
> lib/librte_eal/common/include/rte_common.h | 10 ++++++++++
> lib/librte_eal/linuxapp/eal/eal_timer.c | 2 +-
> 3 files changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/lib/librte_eal/common/eal_common_timer.c
> b/lib/librte_eal/common/eal_common_timer.c
> index dcf26bfea..1358bbed0 100644
> --- a/lib/librte_eal/common/eal_common_timer.c
> +++ b/lib/librte_eal/common/eal_common_timer.c
> @@ -69,7 +69,7 @@ estimate_tsc_freq(void)
> /* assume that the sleep(1) will sleep for 1 second */
> uint64_t start = rte_rdtsc();
> sleep(1);
> - return rte_rdtsc() - start;
> + return RTE_ALIGN_MUL_NEAR(rte_rdtsc() - start, 1E7);
> }
>
> void
> @@ -83,7 +83,7 @@ set_tsc_freq(void)
> if (!freq)
> freq = estimate_tsc_freq();
>
> - RTE_LOG(DEBUG, EAL, "TSC frequency is ~%" PRIu64 " KHz\n", freq / 1000);
> + RTE_LOG(INFO, EAL, "TSC frequency is ~%" PRIu64 " Hz\n", freq);
> eal_tsc_resolution_hz = freq;
> }
>
> diff --git a/lib/librte_eal/common/include/rte_common.h
> b/lib/librte_eal/common/include/rte_common.h
> index 66cdf60b2..e374b16b1 100644
> --- a/lib/librte_eal/common/include/rte_common.h
> +++ b/lib/librte_eal/common/include/rte_common.h
> @@ -248,6 +248,16 @@ static void __attribute__((destructor(RTE_PRIO(prio)),
> used)) func(void)
> #define RTE_ALIGN_MUL_FLOOR(v, mul) \
> ((v / ((typeof(v))(mul))) * (typeof(v))(mul))
>
> +/**
> + * Macro to align a value to the nearest multiple of given value.
> + */
> +#define RTE_ALIGN_MUL_NEAR(v, mul) \
> + ({ \
> + typeof(v) ceil = RTE_ALIGN_MUL_CEIL(v, mul); \
> + typeof(v) floor = RTE_ALIGN_MUL_FLOOR(v, mul); \
> + (ceil - v) > (v - floor) ? floor: ceil; \
> + })
> +
Probably it is better to have two patches.
First patch to add new API along with unit testcase.
Second patch to roundup tsc frequency when estimating it.
> /**
> * Checks if a pointer is aligned to a given power-of-two value
> *
> diff --git a/lib/librte_eal/linuxapp/eal/eal_timer.c
> b/lib/librte_eal/linuxapp/eal/eal_timer.c
> index bc8f05199..864d6ef29 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_timer.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_timer.c
> @@ -248,7 +248,7 @@ get_tsc_freq(void)
>
> double secs = (double)ns/NS_PER_SEC;
> tsc_hz = (uint64_t)((end - start)/secs);
> - return tsc_hz;
> + return RTE_ALIGN_MUL_NEAR(tsc_hz, 1E7);
> }
> #endif
> return 0;
> --
> 2.19.2
>
