On Wed, 2007-07-11 at 17:16 +0530, Balbir Singh wrote: > Zhang, Yanmin wrote: > > struct task_delay_info is used by per process block I/O delay statistics > > feature which is useful in kernel. This struct is not optimized. > > > > My patch against kernel 2.6.22 shrinks it a half. > > > > 1) Delete blkio_start and blkio_end. As the collection happens in > > io_schedule and io_schedule_timeout, we use local variables to > > replace them; > > 2) Delete lock. The change to the protected data has no nested cases. > > In addition, the result is for performance data collection, so it’s > > unnecessary to add such lock. > > 3) Delete flags. It just has one value. Use the most significant bit of > > blkio_delay (64 bits) to mark it.. > > > > > > Signed-off-by: Zhang Yanmin <[EMAIL PROTECTED]> > > Hi, Yanmin, > > Did you see any particular performance issues with the delay accounting > patches? Is the patch tested; could you please provide test results? It's hard to find an appropriate benchmark to test it. Anyway, I used sysbench to test it on my x86_64 machine. My machine has 16 logical cpu, dual-core+hyperThread. memory is 8GB and disk is one SATA.
I tested both sequence and rand. 1) seq read/write:use command line: echo "3">/proc/sys/vm/drop_caches; sysbench --test=fileio --file-test-mode=seqrewr --num-threads=32 --file-total-size=1500M --max-requests=150000 --max-time=3000 run; Run the command for 20 times and get average result: Without patch: 49.7511Mb/sec With patch: 51.6557Mb/sec Improvement: 3.8% 2) Rand read/write:use command line: echo "3">/proc/sys/vm/drop_caches; sysbench --test=fileio --file-test-mode=rndrw --num-threads=32 --file-total-size=800M --max-requests=15000 --max-time=3000 run; Run the command for 10 times and get average result: Without patch: 7.25657Mb/sec With patch: 7.35052Mb/sec Improvement: 1.3% I didn't use application to read the delay accounting info. If I did, I guess the improvement is better. > > Meanwhile, I'll review these patches and I am correcting Shailabh's id > to his new email id. Thanks. Yanmin - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
