Add peak_t, for tracking allocator net max.

This commit is contained in:
David Goldblatt 2020-05-27 14:30:28 -07:00 committed by David Goldblatt
parent 17a64fe91c
commit fe7108305a
3 changed files with 85 additions and 0 deletions

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@ -222,6 +222,7 @@ TESTS_UNIT := \
$(srcroot)test/unit/pa.c \
$(srcroot)test/unit/pack.c \
$(srcroot)test/unit/pages.c \
$(srcroot)test/unit/peak.c \
$(srcroot)test/unit/ph.c \
$(srcroot)test/unit/prng.c \
$(srcroot)test/unit/prof_accum.c \

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@ -0,0 +1,37 @@
#ifndef JEMALLOC_INTERNAL_PEAK_H
#define JEMALLOC_INTERNAL_PEAK_H
typedef struct peak_s peak_t;
struct peak_s {
/* The highest recorded peak value, after adjustment (see below). */
uint64_t cur_max;
/*
* The difference between alloc and dalloc at the last set_zero call;
* this lets us cancel out the appropriate amount of excess.
*/
uint64_t adjustment;
};
#define PEAK_INITIALIZER {0, 0}
static inline uint64_t
peak_max(peak_t *peak) {
return peak->cur_max;
}
static inline void
peak_update(peak_t *peak, uint64_t alloc, uint64_t dalloc) {
int64_t candidate_max = (int64_t)(alloc - dalloc - peak->adjustment);
if (candidate_max > (int64_t)peak->cur_max) {
peak->cur_max = candidate_max;
}
}
/* Resets the counter to zero; all peaks are now relative to this point. */
static inline void
peak_set_zero(peak_t *peak, uint64_t alloc, uint64_t dalloc) {
peak->cur_max = 0;
peak->adjustment = alloc - dalloc;
}
#endif /* JEMALLOC_INTERNAL_PEAK_H */

47
test/unit/peak.c Normal file
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@ -0,0 +1,47 @@
#include "test/jemalloc_test.h"
#include "jemalloc/internal/peak.h"
TEST_BEGIN(test_peak) {
peak_t peak = PEAK_INITIALIZER;
expect_u64_eq(0, peak_max(&peak),
"Peak should be zero at initialization");
peak_update(&peak, 100, 50);
expect_u64_eq(50, peak_max(&peak),
"Missed update");
peak_update(&peak, 100, 100);
expect_u64_eq(50, peak_max(&peak), "Dallocs shouldn't change peak");
peak_update(&peak, 100, 200);
expect_u64_eq(50, peak_max(&peak), "Dallocs shouldn't change peak");
peak_update(&peak, 200, 200);
expect_u64_eq(50, peak_max(&peak), "Haven't reached peak again");
peak_update(&peak, 300, 200);
expect_u64_eq(100, peak_max(&peak), "Missed an update.");
peak_set_zero(&peak, 300, 200);
expect_u64_eq(0, peak_max(&peak), "No effect from zeroing");
peak_update(&peak, 300, 300);
expect_u64_eq(0, peak_max(&peak), "Dalloc shouldn't change peak");
peak_update(&peak, 400, 300);
expect_u64_eq(0, peak_max(&peak), "Should still be net negative");
peak_update(&peak, 500, 300);
expect_u64_eq(100, peak_max(&peak), "Missed an update.");
/*
* Above, we set to zero while a net allocator; let's try as a
* net-deallocator.
*/
peak_set_zero(&peak, 600, 700);
expect_u64_eq(0, peak_max(&peak), "No effect from zeroing.");
peak_update(&peak, 600, 800);
expect_u64_eq(0, peak_max(&peak), "Dalloc shouldn't change peak.");
peak_update(&peak, 700, 800);
expect_u64_eq(0, peak_max(&peak), "Should still be net negative.");
peak_update(&peak, 800, 800);
expect_u64_eq(100, peak_max(&peak), "Missed an update.");
}
TEST_END
int
main(void) {
return test_no_reentrancy(
test_peak);
}