* Li Zefan <lizf@xxxxxxxxxxxxxx> wrote: > Ingo Molnar wrote: > > * Li Zefan <lizf@xxxxxxxxxxxxxx> wrote: > > > >> From: Shawn Du <duyuyang@xxxxxxxxx> > >> > >> Though one can specify '-d /dev/sda1' when using blktrace, it > >> still traces the whole sda. > >> > >> To support per-partition tracing, when we start tracing, we > >> initialize bt->start_lba and bt->end_lba to the start and end > >> sector of that partition. > >> > >> Note some actions are per device, thus we don't filter 0-sector > >> events. > >> > >> The original patch and discussion can be found here: > >> http://marc.info/?l=linux-btrace&m=122949374214540&w=2 > >> > >> Signed-off-by: Shawn Du <duyuyang@xxxxxxxxx> > >> Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx> > > > > Thanks - beyond the small detail i mailed about a few minutes ago > > the series looks good: i'll queue this up in tracing/blktrace unless > > Jens has second thoughts. > > > > Lets note that this approach still has the (long existing) > > limitation that only one device can be block-traced at a time. > > > > No, both userspace blktrace and ftrace-plugin trace can trace > more than one device at a time. > > # btrace /dev/sda /dev/dm-0 > > or > > # echo 1 > /sys/block/sda/trace/enable > # echo 1 > /sys/block/dm-0/trace/enable When they are independent - but not multiple partitions at a time: [root@aldebaran ~]# echo 1 > /sys/block/sda/sda1/trace/enable [root@aldebaran ~]# echo 1 > /sys/block/sda/sda2/trace/enable -bash: echo: write error: Device or resource busy [root@aldebaran ~]# Nor did i see any "trace all block IO in the system" kind of functionality in blktrace. (or maybe there's one that i missed?) > > Furthermore, various other aspects of act_log_check() itself > > could be expressed in terms of per tracepoint filters as well: > > the PID filter field for example - which is supported in the > > ioctl ABI but currently not exposed in the user-space blktrace > > utility. Same goes for the action mask which is frequently used. > > > > Actually action mask can be specified by 'blktrace -a/-A > mask/mask_name' Yes, this is what i meant by "which is frequently used". Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-btrace" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
