0c4e774fad
Caching registers value into an array. Got about 4% speed up
of perf_reg_value function for report command processing
dwarf unwind stacks.
Output from report over 1.5 GB data with DWARF unwind stacks:
(TODO fix perf diff)
current code:
5.84% perf perf [.] perf_reg_value
change:
1.94% perf perf [.] perf_reg_value
And little bit of overall speed up:
(perf stat -r 5 -e '{cycles,instructions}:u' ...)
current code:
310,298,611,754 cycles ( +- 0.33% )
439,669,689,341 instructions ( +- 0.03% )
188.656753166 seconds time elapsed ( +- 0.82% )
change:
291,315,329,878 cycles ( +- 0.22% )
391,763,485,304 instructions ( +- 0.03% )
180.742249687 seconds time elapsed ( +- 0.64% )
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1401892622-30848-2-git-send-email-jolsa@kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
27 lines
449 B
C
27 lines
449 B
C
#include <errno.h>
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#include "perf_regs.h"
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#include "event.h"
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int perf_reg_value(u64 *valp, struct regs_dump *regs, int id)
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{
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int i, idx = 0;
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u64 mask = regs->mask;
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if (regs->cache_mask & (1 << id))
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goto out;
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if (!(mask & (1 << id)))
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return -EINVAL;
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for (i = 0; i < id; i++) {
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if (mask & (1 << i))
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idx++;
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}
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regs->cache_mask |= (1 << id);
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regs->cache_regs[id] = regs->regs[idx];
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out:
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*valp = regs->cache_regs[id];
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return 0;
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}
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