On Wed, Jun 1, 2022 at 9:30 AM Bill Wendling <morbo@xxxxxxxxxx> wrote: > > From: Bill Wendling <isanbard@xxxxxxxxx> > > Clang can be more aggressive at inlining than GCC and will fully inline > calls to measure(). This can mess with the counter overflow check. To > set up the PMC overflow, check_counter_overflow() first records the > number of instructions retired in an invocation of measure() and checks > to see that subsequent calls to measure() retire the same number of > instructions. If inlining occurs, those numbers can be different and the > overflow test fails. > > FAIL: overflow: cntr-0 > PASS: overflow: status-0 > PASS: overflow: status clear-0 > PASS: overflow: irq-0 > FAIL: overflow: cntr-1 > PASS: overflow: status-1 > PASS: overflow: status clear-1 > PASS: overflow: irq-1 > FAIL: overflow: cntr-2 > PASS: overflow: status-2 > PASS: overflow: status clear-2 > PASS: overflow: irq-2 > FAIL: overflow: cntr-3 > PASS: overflow: status-3 > PASS: overflow: status clear-3 > PASS: overflow: irq-3 > > Disabling inlining of measure() keeps the assumption that all calls to > measure() retire the same number of instructions. > > Cc: Jim Mattson <jmattson@xxxxxxxxxx> > Signed-off-by: Bill Wendling <morbo@xxxxxxxxxx> Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
