Messages in this thread | | | Subject | Re: perf top for arm64? | From | John Garry <> | Date | Tue, 10 Dec 2019 16:52:52 +0000 |
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On 10/12/2019 16:36, Jiri Olsa wrote: > On Tue, Dec 10, 2019 at 04:13:49PM +0000, John Garry wrote: >> Hi all, >> >> I find to my surprise that "perf top" does not work for arm64: >> >> root@ubuntu:/home/john/linux# tools/perf/perf top >> Couldn't read the cpuid for this machine: No such file or directory >
Hi Jirka,
> there was recent change that check on cpuid and quits: > 608127f73779 perf top: Initialize perf_env->cpuid, needed by the per arch annotation init routine >
ok, this is new code. I obviously didn't check the git history...
But, apart from this, there are many other places where get_cpuid() is called. I wonder what else we're missing out on, and whether we should still add it.
Thanks, John
> Arnaldo, > maybe this should be just a warning/info, because it seems to be related > to annotations only..? > > get_cpuid is defined only for s390/x86/powerpc, so I guess it won't work > on the rest as well > > jirka > >> >> That's v5.5-rc1 release. >> >> It seems that we are just missing an arm64 version of get_cpuid() - with the >> patch below, I now get as hoped: >> >> PerfTop: 32857 irqs/sec kernel:85.0% exact: 0.0% lost: 0/0 drop: 0/0 >> [4000Hz cycles], (all, 64 CPUs) >> ------------------------------------------------------------------------------- >> >> 8.99% [kernel] [k] arm_smmu_cmdq_issue_cmdlist >> 5.80% [kernel] [k] __softirqentry_text_start >> 4.49% [kernel] [k] _raw_spin_unlock_irqrestore >> 3.48% [kernel] [k] el0_svc_common.constprop.2 >> 3.37% [kernel] [k] _raw_write_lock_irqsave >> 3.28% [kernel] [k] __local_bh_enable_ip >> 3.05% [kernel] [k] __blk_complete_request >> 2.07% [kernel] [k] queued_spin_lock_slowpath >> 1.93% [vdso] [.] 0x0000000000000484 >> >> >> Was this just missed? Or is there a good reason to omit? >> >> Thanks, >> John >> >> --->8--- >> >> Subject: [PATCH] perf: Add perf top support for arm64 >> >> Copied from get_cpuid_str() essentially... >> >> Signed-off-by: John Garry <john.garry@huawei.com> >> >> diff --git a/tools/perf/arch/arm64/util/header.c >> b/tools/perf/arch/arm64/util/header.c >> index a32e4b72a98f..ecd1f86e29cc 100644 >> --- a/tools/perf/arch/arm64/util/header.c >> +++ b/tools/perf/arch/arm64/util/header.c >> @@ -1,10 +1,12 @@ >> #include <stdio.h> >> #include <stdlib.h> >> #include <perf/cpumap.h> >> +#include <util/cpumap.h> >> #include <internal/cpumap.h> >> #include <api/fs/fs.h> >> #include "debug.h" >> #include "header.h" >> +#include <errno.h> >> >> #define MIDR "/regs/identification/midr_el1" >> #define MIDR_SIZE 19 >> @@ -12,6 +14,59 @@ >> #define MIDR_VARIANT_SHIFT 20 >> #define MIDR_VARIANT_MASK (0xf << MIDR_VARIANT_SHIFT) >> >> +int >> +get_cpuid(char *buffer, size_t sz) >> +{ >> + char *buf = NULL; >> + char path[PATH_MAX]; >> + const char *sysfs = sysfs__mountpoint(); >> + int cpu; >> + u64 midr = 0; >> + FILE *file; >> + >> + if (!sysfs) >> + return EINVAL; >> + >> + buf = malloc(MIDR_SIZE); >> + if (!buf) >> + return EINVAL; >> + >> + /* read midr from list of cpus mapped to this pmu */ >> + for (cpu = 0; cpu < cpu__max_present_cpu(); cpu++) { >> + scnprintf(path, sz, "%s/devices/system/cpu/cpu%d"MIDR, >> + sysfs, cpu); >> + >> + file = fopen(path, "r"); >> + if (!file) { >> + pr_debug("fopen failed for file %s\n", path); >> + continue; >> + } >> + >> + if (!fgets(buf, MIDR_SIZE, file)) { >> + fclose(file); >> + continue; >> + } >> + fclose(file); >> + >> + /* Ignore/clear Variant[23:20] and >> + * Revision[3:0] of MIDR >> + */ >> + midr = strtoul(buf, NULL, 16); >> + midr &= (~(MIDR_VARIANT_MASK | MIDR_REVISION_MASK)); >> + scnprintf(buffer, MIDR_SIZE, "0x%016lx", midr); >> + /* got midr break loop */ >> + break; >> + } >> + >> + if (!midr) { >> + pr_err("failed to get cpuid string\n"); >> + free(buf); >> + return EINVAL; >> + } >> + return 0; >> +} >> + >> > > . >
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