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The number of hardware counters is limited. The multiplexing feature enables OProfile to gather more events than counters are provided by the hardware. This is realized by switching between events at an user specified time interval. A new file (/dev/oprofile/time_slice) is added for the user to specify the timer interval in ms. If the number of events to profile is higher than the number of hardware counters available, the patch will schedule a work queue that switches the event counter and re-writes the different sets of values into it. The switching mechanism needs to be implemented for each architecture to support multiplexing. This patch only implements AMD CPU support, but multiplexing can be easily extended for other models and architectures. There are follow-on patches that rework parts of this patch. Signed-off-by: Jason Yeh <jason.yeh@amd.com> Signed-off-by: Robert Richter <robert.richter@amd.com>
89 lines
2.4 KiB
C
89 lines
2.4 KiB
C
/**
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* @file oprofile_stats.c
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*
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* @remark Copyright 2002 OProfile authors
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* @remark Read the file COPYING
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*
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* @author John Levon
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*/
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#include <linux/oprofile.h>
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#include <linux/smp.h>
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#include <linux/cpumask.h>
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#include <linux/threads.h>
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#include "oprofile_stats.h"
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#include "cpu_buffer.h"
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struct oprofile_stat_struct oprofile_stats;
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#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
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atomic_t multiplex_counter;
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#endif
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void oprofile_reset_stats(void)
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{
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struct oprofile_cpu_buffer *cpu_buf;
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int i;
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for_each_possible_cpu(i) {
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cpu_buf = &per_cpu(cpu_buffer, i);
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cpu_buf->sample_received = 0;
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cpu_buf->sample_lost_overflow = 0;
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cpu_buf->backtrace_aborted = 0;
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cpu_buf->sample_invalid_eip = 0;
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}
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atomic_set(&oprofile_stats.sample_lost_no_mm, 0);
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atomic_set(&oprofile_stats.sample_lost_no_mapping, 0);
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atomic_set(&oprofile_stats.event_lost_overflow, 0);
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atomic_set(&oprofile_stats.bt_lost_no_mapping, 0);
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#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
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atomic_set(&multiplex_counter, 0);
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#endif
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}
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void oprofile_create_stats_files(struct super_block *sb, struct dentry *root)
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{
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struct oprofile_cpu_buffer *cpu_buf;
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struct dentry *cpudir;
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struct dentry *dir;
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char buf[10];
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int i;
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dir = oprofilefs_mkdir(sb, root, "stats");
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if (!dir)
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return;
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for_each_possible_cpu(i) {
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cpu_buf = &per_cpu(cpu_buffer, i);
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snprintf(buf, 10, "cpu%d", i);
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cpudir = oprofilefs_mkdir(sb, dir, buf);
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/* Strictly speaking access to these ulongs is racy,
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* but we can't simply lock them, and they are
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* informational only.
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*/
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oprofilefs_create_ro_ulong(sb, cpudir, "sample_received",
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&cpu_buf->sample_received);
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oprofilefs_create_ro_ulong(sb, cpudir, "sample_lost_overflow",
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&cpu_buf->sample_lost_overflow);
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oprofilefs_create_ro_ulong(sb, cpudir, "backtrace_aborted",
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&cpu_buf->backtrace_aborted);
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oprofilefs_create_ro_ulong(sb, cpudir, "sample_invalid_eip",
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&cpu_buf->sample_invalid_eip);
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}
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oprofilefs_create_ro_atomic(sb, dir, "sample_lost_no_mm",
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&oprofile_stats.sample_lost_no_mm);
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oprofilefs_create_ro_atomic(sb, dir, "sample_lost_no_mapping",
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&oprofile_stats.sample_lost_no_mapping);
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oprofilefs_create_ro_atomic(sb, dir, "event_lost_overflow",
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&oprofile_stats.event_lost_overflow);
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oprofilefs_create_ro_atomic(sb, dir, "bt_lost_no_mapping",
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&oprofile_stats.bt_lost_no_mapping);
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#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
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oprofilefs_create_ro_atomic(sb, dir, "multiplex_counter",
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&multiplex_counter);
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#endif
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}
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