We made the test today on our custom board based on a OMAP L138 (ARM9) using Linux 3.0 with high resolution timers enabled in the kernel (without RT patch). Our test ran for more than 4 hours without any issue. So it seems that this issue doesn't appear on all the ARM platforms. Best regards Fernando -----Original Message----- From: linux-rt-users-owner@xxxxxxxxxxxxxxx [mailto:linux-rt-users-owner@xxxxxxxxxxxxxxx] On Behalf Of Sankara Muthukrishnan Sent: terça-feira, 6 de Setembro de 2011 05:08 To: Michael Mueller Cc: Thomas Gleixner; linux-rt-users Subject: Re: Issue (NOT RELATED TO RT-PATCH) with clock_gettime / clock_nanosleep APIs with high resolution timer on panda board >On Fri, Sep 2, 2011 at 6:29 AM, Michael Mueller <ss7box@xxxxxxxxx> wrote: > > >> > > > >> > > clock_gettime(CLOCK_MONOTONIC, &prev); > >> > > while (1) { > >> > > clock_gettime(CLOCK_MONOTONIC, &curr); > >> > > if (curr < prev) /* Use a proper compare function for > >> > > timespec! */ > >> > > printf(.....); > >> > > prev = curr; > >> > > } I have tried this on 2 panda boards. Both of them fail this simple test with vanilla (both single core and SMP) kernels (2.6.39-rc4 mainline with high-resolution timer patch, 3.0.1 mainline with high-resolution timer patch, 3.1-rc2 OMAP git tree without any patch but with high-resolution timer enabled) within a few seconds to an hour. Time goes backwards from as low as 234 nsec to 53 usec. The problem does not reproduce without high resolution timer (i.e by enabling 32 KHz timer in kernel config) for several hours of testing. Everyone, could you please try this test on any other ARM boards (and x86 machines?) with high resolution timer support? -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
