On Wed, Oct 02, 2024 at 07:56:36PM +0300, Isaac Boukris wrote:
> The CPU value is often not accurate, allow overriding it based
> on info from the host OS.
>
> On Linux X86, if the tsc_known_freq cpu flag is missing, it means
> the kernel doesn't trust it and calculates its own. We should do
> the same to avoid drift.
>
> On freebsd we have access to the kernel tsc_hz value, just use it.
>
> Signed-off-by: Isaac Boukris <ibouk...@gmail.com>
> ---
Looks good to me. Hope to test it out soon on my systems to see how it
goes.
One comment inline below.
/Bruce
> lib/eal/common/eal_common_timer.c | 3 +-
> lib/eal/common/eal_private.h | 2 +-
> lib/eal/freebsd/eal_timer.c | 8 +++--
> lib/eal/linux/eal_timer.c | 53 +++++++++++++++++++++++++++++--
> lib/eal/windows/eal_timer.c | 5 ++-
> 5 files changed, 62 insertions(+), 9 deletions(-)
>
> diff --git a/lib/eal/common/eal_common_timer.c
> b/lib/eal/common/eal_common_timer.c
> index c5c4703f15..e00be0a5c8 100644
> --- a/lib/eal/common/eal_common_timer.c
> +++ b/lib/eal/common/eal_common_timer.c
> @@ -66,8 +66,7 @@ set_tsc_freq(void)
> }
>
> freq = get_tsc_freq_arch();
> - if (!freq)
> - freq = get_tsc_freq();
> + freq = get_tsc_freq(freq);
> if (!freq)
> freq = estimate_tsc_freq();
>
> diff --git a/lib/eal/common/eal_private.h b/lib/eal/common/eal_private.h
> index af09620426..bb315dab04 100644
> --- a/lib/eal/common/eal_private.h
> +++ b/lib/eal/common/eal_private.h
> @@ -374,7 +374,7 @@ void set_tsc_freq(void);
> *
> * This function is private to the EAL.
> */
> -uint64_t get_tsc_freq(void);
> +uint64_t get_tsc_freq(uint64_t arch_hz);
>
> /**
> * Get TSC frequency if the architecture supports.
> diff --git a/lib/eal/freebsd/eal_timer.c b/lib/eal/freebsd/eal_timer.c
> index 3dd70e24ba..19fc9a7228 100644
> --- a/lib/eal/freebsd/eal_timer.c
> +++ b/lib/eal/freebsd/eal_timer.c
> @@ -26,7 +26,7 @@
> enum timer_source eal_timer_source = EAL_TIMER_TSC;
>
> uint64_t
> -get_tsc_freq(void)
> +get_tsc_freq(uint64_t arch_hz)
> {
> size_t sz;
> int tmp;
> @@ -50,9 +50,13 @@ get_tsc_freq(void)
> sz = sizeof(tsc_hz);
> if (sysctlbyname("machdep.tsc_freq", &tsc_hz, &sz, NULL, 0)) {
> EAL_LOG(WARNING, "%s", strerror(errno));
> - return 0;
> + return arch_hz;
> }
>
> + if (arch_hz && arch_hz - tsc_hz > arch_hz / 100)
Do we not need an "abs()" call on the "arch_hz - tsc_hz" in case tsc_hz is
the bigger value?
