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![Jason Yeh](/assets/img/avatar_default.png)
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>
41 lines
991 B
C
41 lines
991 B
C
/**
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* @file oprof.h
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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 <levon@movementarian.org>
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*/
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#ifndef OPROF_H
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#define OPROF_H
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int oprofile_setup(void);
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void oprofile_shutdown(void);
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int oprofilefs_register(void);
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void oprofilefs_unregister(void);
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int oprofile_start(void);
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void oprofile_stop(void);
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struct oprofile_operations;
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extern unsigned long oprofile_buffer_size;
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extern unsigned long oprofile_cpu_buffer_size;
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extern unsigned long oprofile_buffer_watershed;
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extern struct oprofile_operations oprofile_ops;
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extern unsigned long oprofile_started;
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extern unsigned long oprofile_backtrace_depth;
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extern unsigned long timeout_jiffies;
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struct super_block;
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struct dentry;
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void oprofile_create_files(struct super_block *sb, struct dentry *root);
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void oprofile_timer_init(struct oprofile_operations *ops);
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int oprofile_set_backtrace(unsigned long depth);
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int oprofile_set_timeout(unsigned long time);
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#endif /* OPROF_H */
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