Commit 3312405

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Fix incorrect DROP_SIZE usage

Previously, measure() only recorded timings for indices in the middle range [DROP_SIZE, N_MEASURES - DROP_SIZE), while update_statistics() assumed all entries were starting available from index 10. This mismatch allowed zero-valued exec_times from unmeasured head and tail indices to be included in the t-test, reducing sample means, inflating variances, and suppressing the t-value, which may lead to incorrect results or prevent detection thresholds from being reached. After the fix, all samples are measured and update_statistics() discards DROP_SIZE samples at both ends. This ensures correct sample accounting, prevents overestimating the number of measurements required, and avoids false negatives due to uninitialized timing data. Change-Id: Ibb1515043da5f56d72fe34fd5c78e2283df9a993

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2 files changed

-6

lines changed

dudect
- constant.c
- fixture.c

2 files changed

-6

lines changed

`‎dudect/constant.c`

Lines changed: 5 additions & 5 deletions

Original file line number	Diff line number	Diff line change
`@@ -77,7 +77,7 @@ bool measure(int64_t *before_ticks,`
`77`	`77`
`78`	`78`	`switch (mode) {`
`79`	`79`	`case DUT(insert_head):`
`80`		`- for (size_t i = DROP_SIZE; i < N_MEASURES-DROP_SIZE; i++) {`
	`80`	`+ for (size_t i = 0; i < N_MEASURES; i++) {`
`81`	`81`	`char *s = get_random_string();`
`82`	`82`	`dut_new();`
`83`	`83`	`dut_insert_head(`
`@@ -94,7 +94,7 @@ bool measure(int64_t *before_ticks,`
`94`	`94`	`}`
`95`	`95`	`break;`
`96`	`96`	`case DUT(insert_tail):`
`97`		`- for (size_t i = DROP_SIZE; i < N_MEASURES-DROP_SIZE; i++) {`
	`97`	`+ for (size_t i = 0; i < N_MEASURES; i++) {`
`98`	`98`	`char *s = get_random_string();`
`99`	`99`	`dut_new();`
`100`	`100`	`dut_insert_head(`
`@@ -111,7 +111,7 @@ bool measure(int64_t *before_ticks,`
`111`	`111`	`}`
`112`	`112`	`break;`
`113`	`113`	`case DUT(remove_head):`
`114`		`- for (size_t i = DROP_SIZE; i < N_MEASURES-DROP_SIZE; i++) {`
	`114`	`+ for (size_t i = 0; i < N_MEASURES; i++) {`
`115`	`115`	`dut_new();`
`116`	`116`	`dut_insert_head(`
`117`	`117`	`get_random_string(),`
`@@ -129,7 +129,7 @@ bool measure(int64_t *before_ticks,`
`129`	`129`	`}`
`130`	`130`	`break;`
`131`	`131`	`case DUT(remove_tail):`
`132`		`- for (size_t i = DROP_SIZE; i < N_MEASURES-DROP_SIZE; i++) {`
	`132`	`+ for (size_t i = 0; i < N_MEASURES; i++) {`
`133`	`133`	`dut_new();`
`134`	`134`	`dut_insert_head(`
`135`	`135`	`get_random_string(),`
`@@ -147,7 +147,7 @@ bool measure(int64_t *before_ticks,`
`147`	`147`	`}`
`148`	`148`	`break;`
`149`	`149`	`default:`
`150`		`- for (size_t i = DROP_SIZE; i < N_MEASURES-DROP_SIZE; i++) {`
	`150`	`+ for (size_t i = 0; i < N_MEASURES; i++) {`
`151`	`151`	`dut_new();`
`152`	`152`	`dut_insert_head(`
`153`	`153`	`get_random_string(),`

`‎dudect/fixture.c`

Lines changed: 1 addition & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -103,7 +103,7 @@ static void update_statistics(const int64_t *exec_times,`
`103`	`103`	`uint8_t *classes,`
`104`	`104`	`int64_t *percentiles)`
`105`	`105`	`{`
`106`		`- for (size_t i = 0; i < N_MEASURES; i++) {`
	`106`	`+ for (size_t i = DROP_SIZE; i < N_MEASURES-DROP_SIZE; i++) {`
`107`	`107`	`int64_t difference = exec_times[i];`
`108`	`108`	`/* CPU cycle counter overflowed or dropped measurement */`
`109`	`109`	`if (difference <= 0)`

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Commit 3312405

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2 files changed

2 files changed

`‎dudect/constant.c`

`‎dudect/fixture.c`

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