-----邮件原件----- 发件人: Jerin Jacob [mailto:jerinjac...@gmail.com] 发送时间: 2020年3月9日 23:43 收件人: Linhaifeng <haifeng....@huawei.com> 抄送: dev@dpdk.org; tho...@monjalon.net; Lilijun (Jerry) <jerry.lili...@huawei.com>; chenchanghu <chenchan...@huawei.com>; xudingke <xudin...@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....@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....@huawei.com>
