From: Bruce Richardson <bruce.richardson@intel.com>
To: Jim Harris <james.r.harris@intel.com>
Cc: dev@dpdk.org, anatoly.burakov@intel.com
Subject: Re: [dpdk-dev] [PATCH v5] eal: use memzone to share tsc hz with secondary processes
Date: Tue, 27 Aug 2019 09:14:01 +0100 [thread overview]
Message-ID: <20190827081400.GA1740@bricha3-MOBL.ger.corp.intel.com> (raw)
In-Reply-To: <156682708634.28714.543470193614987025.stgit@jrharri1-skx>
On Mon, Aug 26, 2019 at 06:44:46AM -0700, Jim Harris wrote:
> Ideally, get_tsc_freq_arch() is able to provide the
> TSC rate using arch-specific means. When that is not
> possible, DPDK reverts to calculating the TSC rate with
> a 100ms nanosleep or 1s sleep. The latter occurs more
> frequently in VMs which often do not have access to the
> data they need from arch-specific means (CPUID leaf 0x15
> or MSR 0xCE on x86).
>
> In secondary processes, the extra 100ms is especially
> noticeable and consumes the bulk of rte_eal_init()
> execution time. To resolve this extra delay, have
> the primary process put the TSC rate into a shared
> memory region that the secondary process can lookup.
>
> Reduces rte_eal_init() execution time in a secondary
> process from 165ms to 66ms on my test system.
>
> Signed-off-by: Jim Harris <james.r.harris@intel.com>
> ---
I think using shared memory is a lot simpler to manage, so LGTM.
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
next prev parent reply other threads:[~2019-08-27 8:14 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-22 8:42 [dpdk-dev] [PATCH v3] timer: use rte_mp_msg to get freq from primary process Jim Harris
2019-08-26 13:39 ` [dpdk-dev] [PATCH v4] eal: use memzone to share tsc hz with secondary processes Jim Harris
2019-08-26 13:44 ` [dpdk-dev] [PATCH v5] " Jim Harris
2019-08-27 8:14 ` Bruce Richardson [this message]
2019-08-27 12:04 ` Burakov, Anatoly
2019-08-27 12:48 ` Bruce Richardson
2019-08-28 9:01 ` Burakov, Anatoly
2019-08-27 14:00 ` Bruce Richardson
2019-08-27 16:16 ` [dpdk-dev] [PATCH v6] eal: add tsc_hz to rte_mem_config Jim Harris
2019-10-07 15:28 ` [dpdk-dev] [PATCH v6 RESEND] " Jim Harris
2019-10-08 8:38 ` Bruce Richardson
2019-10-21 8:23 ` David Marchand
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