Exposing Zone Sleeps

[jhell]

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On 05/24/2010 18:26, Sean Bruno wrote:
> Find attached a patch against -CURRENT.
> 
> This update exposes a counter that indicates the number of times that we
> sleep when attempting to allocate a slab from the keg.  In other words,
> the number of times we BLOCK and wait, which is bad.
> 
> This allows differentiation between times when we failed to allocate and
> it was ok and times where we were forced to sleep.  The current FAIL
> counter does not make this distinction.
> 
> Exposes this information via uma_zone_t->uz_sleeps.
> 
> Add a new sysctl to retrieve this information.
> Enhance vmstat -z to retrieve this information.
> 
> We've found this *extremely* useful here at Yahoo in the past and would
> like to commit this if it is acceptable.
> 
> Tested on 32bit and 64bit architectures on 6/7/CURRENT.
> 

Hi Sean,

Nice work on this. I applied this to stable/8 r208530 and I am in the
process of compiling the kernel right now. Everything else has built &
runs as expected "i386". Attached is the adjusted patch which was one
modification to the line number for uz_sleeps in sys/vm/uma_int.h.

8 files changed, 106 insertions(+), 7 deletions(-)

For those wishing to apply this patch and test for them self:

cd /usr/src
patch </path/to/sleep_stat_stable8_r208530.diff
cd /usr/src/include
make obj && make depend && make includes && make install
cd /usr/src/lib/libmemstat
make obj && make depend && make includes && make install
cd /usr/src/usr.bin/vmstat
make obj && make depend && make install
cd /usr/src
make kernel KERNCONF=YOUR_KERN_CONF
reboot

Can't wait to see some results from this & I will report back with
either negative results of the build & run or positive results from the
stats collected.

If there is anything needed feel free to let me know and I will do what
is possible ASAP.

Thanks again,

- -- 

 jhell
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