Hi Rishi and Garrett, On Wed, Mar 3, 2010 at 7:15 PM, naresh kamboju <[email protected]> wrote: > On Wed, Mar 3, 2010 at 5:25 PM, Garrett Cooper <[email protected]> wrote: >> On Wed, Mar 3, 2010 at 3:49 AM, naresh kamboju <[email protected]> >> wrote: >>> On Wed, Mar 3, 2010 at 5:12 PM, Garrett Cooper <[email protected]> wrote: >>>> On Wed, Mar 3, 2010 at 3:33 AM, naresh kamboju <[email protected]> >>>> wrote: >>>>> On Wed, Mar 3, 2010 at 3:15 PM, Rishikesh K Rajak >>>>> <[email protected]> wrote: >>>>>> On Wed, Mar 03, 2010 at 01:18:50AM -0800, Garrett Cooper wrote: >>>>>>> Uh, hold on a sec before we call it good... >>>>>> >>>>>> oh ok, holiding on for bit. >>>>>> >>>>>> Naresh, can you please send a patch with incorporating garret's comment >>>>>> ? >>>>>>>>> + /* Step 3 Implementation */ >>>>>>>>> /* Make sure the two children has been waiting */ >>>>>>>>> - /*do { >>>>>>>>> - sleep(1); >>>>>>>>> + do { >>>>>>>>> sem_getvalue(sem_1, &val); >>>>>>>>> //printf("val = %d\n", val); >>>>>>>>> } while (val != 1); >>>>>>>>> - */ >>>>>>> >>>>>>> Please provide another patch with a limit to this -- >>>>> >>>>> Garrett, >>>>> >>>>> When sem_wait is called 'val' value will be decremented by one. >>>>> To ensure that sem_wait is called, we are checking 'val' value by >>>>> calling sem_getvalue(). in this case we don’t need to decrement the >>>>> values by --. IIUC. >>>>> (snip) >>>>> OTOH, >>>>>>> I get annoyed >>>>>>> with tests that have infinite loops in them because the underlying >>>>>>> functionality is broken. >>>>> I agree with you, having infinite loops in test case is not a good. >>>>> However, in this patch while loop is not infinite loop. It is a >>>>> conditional loop with finite value. >>>>> >>>>> Please let me know if you have any issues. >>>> >>>> The problem was that it wasn't failing properly as stated in the >>>> manpage on mips* (was decrementing past 0) and it was blocking >>>> indefinitely. Hence I had to yank those tests from the default run. >>> do you mean, after applying above patch you have noticed these kind of >>> behavior? >> >> Not with this patch; I've seen this kind of behavior in general under >> odd conditions with my former team's embedded setup running tests with >> POSIX semaphores, so I don't doubt that others could run into the >> similar functional issues given the right conditions. > > Hey Garrett, > > Thanks for you information :-) > > I have tested these on MIPS architecture and reproduced infinite > waiting situation after applying this patch. (with strace no issue > found ex: #strace ./8-1.test) > As you said there may be issues in MIPS-POSIX library. it may take > some time to fix these issues or may not be fixed. > However, I’ll discuss this issue with MIPS folks in different thread. > > ATM, my patch is not a good idea for MIPS architectures. > So, after your comments I have modified my patch and tested. > Here in this latest patch i did not change any thing regarding while loop. > I replaced sleep() in an appropriate place. > It is working fine on X86, ARM and MIPS.
please review the patch. I have tested this patch on X86, ARM and MIPS and results are good. If you feel ok. please commit. otherwise give me your comments. Best regards Naresh Kamboju > > Signed-off-by: Naresh Kamboju < [email protected] > > --- > testcases/open_posix_testsuite/conformance/interfaces/sem_post/8-1.c > | 2 1 + 1 - 0 ! > 1 file changed, 1 insertion(+), 1 deletion(-) > > Index: b/testcases/open_posix_testsuite/conformance/interfaces/sem_post/8-1.c > =================================================================== > --- a/testcases/open_posix_testsuite/conformance/interfaces/sem_post/8-1.c > +++ b/testcases/open_posix_testsuite/conformance/interfaces/sem_post/8-1.c > @@ -161,7 +161,6 @@ int main() > } > fprintf(stderr, "P: child_1:%d forked\n", c_1); > > - sleep(1); > c_2 = fork(); > if (c_2 == 0) > { > @@ -198,6 +197,7 @@ int main() > //printf("val = %d\n", val); > } while (val != 0); > */ > + sleep(1); > /* Ok, let's release the lock */ > fprintf(stderr, "P: release lock\n"); > sem_post(sem); > > > please let me know if you have any issues. > > Best regards, > Naresh Kamboju >> Thanks, >> -Garrett >> >
sem-post-unstable-8-1-fix.patch
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