From: Linhaifeng <haifeng.lin@huawei.com>
To: Jerin Jacob <jerinjacobk@gmail.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
"thomas@monjalon.net" <thomas@monjalon.net>,
"Lilijun (Jerry)" <jerry.lilijun@huawei.com>,
chenchanghu <chenchanghu@huawei.com>,
xudingke <xudingke@huawei.com>
Subject: [dpdk-dev] 答复: [PATCH] cycles: add isb before read cntvct_el0
Date: Tue, 10 Mar 2020 02:39:28 +0000 [thread overview]
Message-ID: <4099DE2E54AFAD489356C6C9161D53339729F32B@DGGEML502-MBX.china.huawei.com> (raw)
In-Reply-To: <CALBAE1MUZ4kXf04yGOxi534KP6N14Yk4OQ-Ww+UMpH6f4doAtA@mail.gmail.com>
-----邮件原件-----
发件人: Jerin Jacob [mailto:jerinjacobk@gmail.com]
发送时间: 2020年3月9日 23:43
收件人: Linhaifeng <haifeng.lin@huawei.com>
抄送: dev@dpdk.org; thomas@monjalon.net; Lilijun (Jerry) <jerry.lilijun@huawei.com>; chenchanghu <chenchanghu@huawei.com>; xudingke <xudingke@huawei.com>
主题: Re: [dpdk-dev] [PATCH] cycles: add isb before read cntvct_el0
On Mon, Mar 9, 2020 at 2:43 PM Linhaifeng <haifeng.lin@huawei.com> wrote:
>
> We nead isb rather than dsb to sync system counter to cntvct_el0.
# Currently rte_rdtsc() does not have dsb. Right? or any barriers.
# Why do you need it? If it regarding, getting accurate value then use rte_rdtsc_precise().
We use rte_get_tsc_cycles get start_value in pmd1 and end_value in pmd2 in our qos module, it works ok in x86 but not ok in arm64.
Then we use rte_mb() to sync instruction but it not work.Because rte_mb is dsb I think it only have affect on memory. cntvct_el0 and system counter is register so I think we should use isb.
It works well after we use isb in multi core scenes.
Use rte_rdtsc_precise is good idea. Maybe use isb replace of rte_mb(dsb) ?
>
> Signed-off-by: Haifeng Lin <haifeng.lin@huawei.com>
next prev parent reply other threads:[~2020-03-10 2:39 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-09 9:13 [dpdk-dev] " Linhaifeng
2020-03-09 9:19 ` David Marchand
2020-03-10 2:51 ` [dpdk-dev] 答复: " Linhaifeng
2020-03-09 15:43 ` [dpdk-dev] " Jerin Jacob
2020-03-10 2:39 ` Linhaifeng [this message]
2020-03-10 7:53 ` Jerin Jacob
2020-03-09 9:22 Linhaifeng
2020-03-10 7:11 ` Gavin Hu
2020-03-10 7:22 ` Linhaifeng
2020-03-10 7:50 ` Jerin Jacob
2020-03-09 10:58 Linhaifeng
2020-03-09 11:05 Linhaifeng
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