Unverified Commit 6524e9b6 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!5670 cpufreq: CPPC: Eliminate the impact of cpc_read() latency error 

Merge Pull Request from: @ci-robot 
 
PR sync from: Zeng Heng <zengheng4@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/QSB3XLFUSLWS4H2YAF2DEAI44VFXEHPO/ 
 
https://gitee.com/openeuler/kernel/issues/I9COT9 
 
Link:https://gitee.com/openeuler/kernel/pulls/5670

 

Reviewed-by: default avatarXiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: default avatarZucheng Zheng <zhengzucheng@huawei.com>
Signed-off-by: default avatarJialin Zhang <zhangjialin11@huawei.com>
parents eecb1823 7404f3db

drivers/cpufreq/cppc_cpufreq.c

+15 −1
Original line number Diff line number Diff line
@@ -357,12 +357,26 @@ static int cppc_get_perf_ctrs_sample(void *val) 
	struct fb_ctr_pair *fb_ctrs = val;

	int cpu = fb_ctrs->cpu;

	int ret;

	unsigned long timeout;



	ret = cppc_get_perf_ctrs(cpu, &fb_ctrs->fb_ctrs_t0);

	if (ret)

		return ret;



	if (likely(!irqs_disabled())) {

		/*

		 * Set 1ms as sampling interval, but never schedule

		 * to the idle task to prevent the AMU counters from

		 * stopping working.

		 */

		timeout = jiffies + msecs_to_jiffies(1);

		while (!time_after(jiffies, timeout))

			cond_resched();



	} else {

		pr_warn_once("CPU%d: Get rate in atomic context", cpu);

		udelay(2); /* 2usec delay between sampling */

	}



	return cppc_get_perf_ctrs(cpu, &fb_ctrs->fb_ctrs_t1);

}