Re: [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression

Linus Torvalds
2016-08-10T20:20:13Z

On Tue, Aug 9, 2016 at 7:33 AM, kernel test robot <xiaolong.ye@intel.com> wrote:
>
> FYI, we noticed a -13.6% regression of aim7.jobs-per-min due to commit:
> 68a9f5e7007c ("xfs: implement iomap based buffered write path")
>
> in testcase: aim7
> on test machine: 48 threads Ivytown Ivy Bridge-EP with 64G memory
> with following parameters:
>
> disk: 1BRD_48G
> fs: xfs
> test: disk_wrt
> load: 3000
> cpufreq_governor: performance

Christop, Dave, was this expected?

>From looking at the numbers, it looks like much more IO going on (and
this less CPU load)..

> 37.23 ± 0% +15.6% 43.04 ± 0% aim7.time.elapsed_time
> 37.23 ± 0% +15.6% 43.04 ± 0% aim7.time.elapsed_time.max
> 6424 ± 1% +31.3% 8432 ± 1% aim7.time.involuntary_context_switches> 4003 ± 0% +28.1% 5129 ± 1% proc-vmstat.nr_active_file
> 979.25 ± 0% +63.7% 1602 ± 1% proc-vmstat.pgactivate
> 4699 ± 3% +162.6% 12340 ± 73% proc-vmstat.pgpgout
> 50.23 ± 19% -27.3% 36.50 ± 17% sched_debug.cpu.cpu_load[1].avg
> 466.50 ± 29% -51.8% 225.00 ± 73% sched_debug.cpu.cpu_load[1].max
> 77.78 ± 33% -50.6% 38.40 ± 57% sched_debug.cpu.cpu_load[1].stddev
> 300.50 ± 33% -52.9% 141.50 ± 48% sched_debug.cpu.cpu_load[2].max
> 1836 ± 10% +65.5% 3039 ± 8% slabinfo.scsi_data_buffer.active_objs
> 1836 ± 10% +65.5% 3039 ± 8% slabinfo.scsi_data_buffer.num_objs
> 431.75 ± 10% +65.6% 715.00 ± 8% slabinfo.xfs_efd_item.active_objs
> 431.75 ± 10% +65.6% 715.00 ± 8% slabinfo.xfs_efd_item.num_objs

but what do I know. Those profiles from the robot are pretty hard to
make sense of.

Linus