Hi Mika, On Wed, 16 Sep 2009 14:17:08 +0300, Mika Kuoppala wrote: > If low priority thread is holding the bus lock while more high > priority threads needs the same i2c bus, priority inversion occurs and > access latency can grow quite large. In my setup i have seen as high as > 150ms access latencies in some workloads when the actual physical > transaction is finished in less than 5ms. > > The following patch (in separate email) fixes the priority > inversion problem described above by converting the i2c bus lock mutex > to rt_mutex. rt_mutex uses priority inheritance: low priority thread > holding the mutex will get a kick if high priority thread is trying > to acquire the lock. Can you please define "get a kick"? I don't know anything about rt_mutex. > > Thanks, > -- Mika > > Mika Kuoppala (1): > i2c: Prevent priority inversion on top of bus lock by converting it > to rt_mutex > > drivers/i2c/i2c-core.c | 13 +++++++------ > include/linux/i2c.h | 3 +-- > 2 files changed, 8 insertions(+), 8 deletions(-) > -- Jean Delvare -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
