On 2015年05月25日 14:40, David Henningsson wrote:
On 2015-05-25 06:49, Hui Wang wrote:
On 32bits OS, this test case fails. The reason is when rewinding to
the middle of a block, some of float parameters in the saved_state
are stored in the memory from FPU registers, and those parameters will
be used for next time to process data with lfe. Here if FPU register
is over 32bits, the storing from FPU register to memory will introduce
some variation, and this small variation will introduce small
variation to the rewinding result.
Very interesting finding. I didn't know that storing things back and
forth to memory could change the computation result.
And the fact that it only happens on 32-bit platforms and only with
optimisations makes it even stranger. Makes me wonder if this is
actually an gcc optimisation bug.
Probably.
So adding the tolerant variation for comparing the rewind result, make
this test case can work on both 64bits OS and 32bits OS.
Signed-off-by: Hui Wang <hui.w...@canonical.com>
---
I wrote a simple testcase to show the variation exists on 32bits OS.
When compile this test case on 64bits OS, it will not fail when running
it; while on 32bits OS if you just compile it without "-O2", this
testcase still pass without any variation, but if you add "-O2" when
compiling it, you will see variation when you running it.
http://pastebin.ubuntu.com/11342537/
src/tests/lfe-filter-test.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/src/tests/lfe-filter-test.c b/src/tests/lfe-filter-test.c
index 2c6d597..50636a9 100644
--- a/src/tests/lfe-filter-test.c
+++ b/src/tests/lfe-filter-test.c
@@ -37,6 +37,7 @@ static uint8_t *ori_sample_ptr;
#define ONE_BLOCK_SAMPLES 4096
#define TOTAL_SAMPLES 8192
+#define TOLERANT_VARIATION 1
static void save_data_block(struct lfe_filter_test *lft, void *d,
pa_memblock *blk) {
uint8_t *dst = d, *src;
@@ -63,15 +64,26 @@ static pa_memblock* generate_data_block(struct
lfe_filter_test *lft, int start)
static int compare_data_block(struct lfe_filter_test *lft, void *a,
void *b) {
int ret = 0;
uint32_t i;
- uint32_t fz = pa_frame_size(lft->ss);
- uint8_t *r = a, *u = b;
- for (i = 0; i < ONE_BLOCK_SAMPLES * fz; i++) {
- if (*r++ != *u++) {
- pa_log_error("lfe-filter-test: test failed, the output
data in the position 0x%x of a block does not equal!\n", i);
- ret = -1;
+ switch (lft->ss->format) {
+ case PA_SAMPLE_S16NE:
+ case PA_SAMPLE_S16RE: {
Do we need to support PA_SAMPLE_S16RE? If not, then just replace with
"assert(PA_SAMPLE_S16NE == lft->ss->format)".
If you need S16RE, then you need to swap the bytes before comparing.
Don't want to support S16RE, will change to assert() in the V2.
+ uint16_t *r = a, *u = b;
+ for (i = 0; i < ONE_BLOCK_SAMPLES; i++) {
+ uint16_t va = *r++, vb = *u++;
+ uint16_t var = (va >= vb) ? (va - vb) : (vb - va);
Agree with Alexander, use abs() here.
Got it, will fix it in the V2. Thanks.
+ if (var > TOLERANT_VARIATION) {
+ pa_log_error("lfe-filter-test: test failed, the
output data in the position 0x%x of a block does not equal!\n", i);
+ ret = -1;
+ break;
+ }
+ }
break;
}
+ default:
+ pa_log_error("lfe-filter-test: not a suppported sample
format yet in this testcase!\n");
+ ret = -1;
+ break;
}
return ret;
}
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