On Wed, 2007-07-18 at 12:30 +0800, Zhang, Yanmin wrote: > 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. Man,
What's your comment about the patch? 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/
