Messages in this thread Patch in this message | | | Subject | perf top for arm64? | From | John Garry <> | Date | Tue, 10 Dec 2019 16:13:49 +0000 |
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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
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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