[dpdk-dev] [PATCH v5 1/2] test/power: add delay before checking cpuinfo cur freq
Richael Zhuang
Richael.Zhuang at arm.com
Wed Apr 21 04:41:05 CEST 2021
> -----Original Message-----
> From: David Hunt <david.hunt at intel.com>
> Sent: Tuesday, April 20, 2021 8:39 PM
> To: Richael Zhuang <Richael.Zhuang at arm.com>; dev at dpdk.org
> Cc: nd <nd at arm.com>; alan.carew at intel.com; stable at dpdk.org; Pablo de
> Lara <pablo.de.lara.guarch at intel.com>
> Subject: Re: [PATCH v5 1/2] test/power: add delay before checking cpuinfo
> cur freq
>
>
> On 15/4/2021 6:59 AM, Richael Zhuang wrote:
> > For some platforms the newly-set frequency may not be effective
> > immediately. If we didn't get the right value from cpuinfo_cur_freq
> > immediately, add 10ms delay each time before rechecking until timeout.
> >
> > From our test, for some arm platforms, it requires up to 700ms when
> > going from a minimum to a maximum frequency. And it's not the
> > driver/software issue.
> >
> > Fixes: ed7c51a6a680 ("app/test: vm power management")
> > Cc: alan.carew at intel.com
> > Cc: stable at dpdk.org
> >
> > Signed-off-by: Richael Zhuang <richael.zhuang at arm.com>
> > ---
> > app/test/test_power_cpufreq.c | 27 ++++++++++++++++++++++-----
> > 1 file changed, 22 insertions(+), 5 deletions(-)
> >
> > diff --git a/app/test/test_power_cpufreq.c
> > b/app/test/test_power_cpufreq.c index 731c6b4dc..d47b3e0a1 100644
> > --- a/app/test/test_power_cpufreq.c
> > +++ b/app/test/test_power_cpufreq.c
> > @@ -8,6 +8,7 @@
> > #include <limits.h>
> > #include <string.h>
> > #include <inttypes.h>
> > +#include <rte_cycles.h>
> >
> > #include "test.h"
> >
> > @@ -44,11 +45,13 @@ static int
> > check_cur_freq(unsigned lcore_id, uint32_t idx)
> > {
> > #define TEST_POWER_CONVERT_TO_DECIMAL 10
> > +#define MAX_LOOP 100
> > FILE *f;
> > char fullpath[PATH_MAX];
> > char buf[BUFSIZ];
> > uint32_t cur_freq;
> > int ret = -1;
> > + int i;
> >
> > if (snprintf(fullpath, sizeof(fullpath),
> > TEST_POWER_SYSFILE_CUR_FREQ, lcore_id) < 0) { @@ -58,13
> +61,27 @@
> > check_cur_freq(unsigned lcore_id, uint32_t idx)
> > if (f == NULL) {
> > return 0;
> > }
> > - if (fgets(buf, sizeof(buf), f) == NULL) {
> > - goto fail_get_cur_freq;
> > + for (i = 0; i < MAX_LOOP; i++) {
> > + fflush(f);
> > + if (fgets(buf, sizeof(buf), f) == NULL)
> > + goto fail_all;
> > +
> > + cur_freq = strtoul(buf, NULL,
> TEST_POWER_CONVERT_TO_DECIMAL);
> > + ret = (freqs[idx] == cur_freq ? 0 : -1);
> > +
> > + if (ret == 0)
> > + break;
> > +
> > + if (fseek(f, 0, SEEK_SET) < 0) {
> > + printf("Fail to set file position indicator to 0\n");
> > + goto fail_all;
> > + }
> > +
> > + /* wait for the value to be updated */
> > + rte_delay_ms(10);
> > }
> > - cur_freq = strtoul(buf, NULL, TEST_POWER_CONVERT_TO_DECIMAL);
> > - ret = (freqs[idx] == cur_freq ? 0 : -1);
> >
> > -fail_get_cur_freq:
> > +fail_all:
> > fclose(f);
> >
> > return ret;
>
> Hi Richael
>
> On your system, is the current cpu frequency found in cpuinfo_cur_freq or in
> scaling_cur_freq? On my system, which uses intel_pstate driver, there is no
> file called cpuinfo_cur_freq, but the test works when I change
> TEST_POWER_SYSFILE_CUR_FREQ to scaling_cur_freq.
>
> I know that's unrelated to your patch above, but it migth be worth using a file
> common to all platforms, or else attempting to open one, and if that fails, try
> open the other.
>
> Rgds,
> Dave.
>
Hi David,
Thanks for review. We have cpuinfo_cur_freq on our platform. For acpi_cpufreq it's also cpuinfo_cur_freq. For pstate, the check is skipped because there is no such file.
Best Regards,
Richael
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