https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98678
John David Anglin <danglin at gcc dot gnu.org> changed:
What |Removed |Added
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Attachment #58500|0 |1
is obsolete| |
--- Comment #13 from John David Anglin <danglin at gcc dot gnu.org> ---
Created attachment 58515
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58515&action=edit
Really fix poll.cc on hppa-linux
hppa-linux doesn't have high resolution timer support. Timer resolutions
range from 1 to 10ms depending on CONFIG_HZ. The ready loop takes about
5ns per call. As a result, we need a lot of iterations to obtain reasonable
accuracy in the ready loop. I reduced the number of iteration in the
wait_until_sys_epoch and wait_until_steady_epoch loops to 1000 so test
would run in a reasonable time. The results for these two loops are
currently not checked.
Here is output on 1GHz c8000 with HZ=250:
dave@atlas:~/gnu/gcc/objdir/hppa-linux-gnu/libstdc++-v3/testsuite$ ./poll.exe
wait_for(0s): 4919957362ns for 100000000 calls, avg 49.1996ns per call
wait_until(system_clock minimum): 22053828859ns for 100000000 calls, avg
220.538ns per call
wait_until(steady_clock minimum): 22277782883ns for 100000000 calls, avg
222.778ns per call
wait_until(system_clock epoch): 3999965336ns for 1000 calls, avg 3.99997e+06ns
per call
wait_until(steady_clock epoch: 3999965335ns for 1000 calls, avg 3.99997e+06ns
per call
wait_for when ready: 519995494ns for 100000000 calls, avg 5.19995ns per call
