On Fri, Apr 22, 2022 at 10:00:59AM -0700, Yang Shi wrote: > On Thu, Apr 21, 2022 at 11:24 PM Aaron Lu <aaron.lu@xxxxxxxxx> wrote: > > > > On Thu, Apr 21, 2022 at 04:34:09PM +0800, ying.huang@xxxxxxxxx wrote: > > > On Thu, 2022-04-21 at 16:17 +0800, Aaron Lu wrote: > > > > On Thu, Apr 21, 2022 at 03:49:21PM +0800, ying.huang@xxxxxxxxx wrote: > > > > ... ... > > > > > > > For swap-in latency, we can use pmbench, which can output latency > > > > > information. > > > > > > > > > > > > > OK, I'll give pmbench a run, thanks for the suggestion. > > > > > > Better to construct a senario with more swapin than swapout. For > > > example, start a memory eater, then kill it later. > > > > What about vm-scalability/case-swapin? > > https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/tree/case-swapin > > > > I think you are pretty familiar with it but still: > > 1) it starts $nr_task processes and each mmaps $size/$nr_task area and > > then consumes the memory, after this, it waits for a signal; > > 2) start another process to consume $size memory to push the memory in > > step 1) to swap device; > > 3) kick processes in step 1) to start accessing their memory, thus > > trigger swapins. The metric of this testcase is the swapin throughput. > > > > I plan to restrict the cgroup's limit to $size. > > > > Considering there is only one NVMe drive attached to node 0, I will run > > the test as described before: > > 1) bind processes to run on node 0, allocate on node 1 to test the > > performance when reclaimer's node id is the same as swap device's. > > 2) bind processes to run on node 1, allocate on node 0 to test the > > performance when page's node id is the same as swap device's. > > > > Ying and Yang, > > > > Let me know what you think about the case used and the way the test is > > conducted. > > Looks fine to me. To measure the latency, you could also try the below > bpftrace script: Yeah, bpftrace can nicely show us the histogram of the latency. The hard part is to integrate bpftrace into LKP framework though. > > #! /usr/bin/bpftrace > > kprobe:swap_readpage > { > @start[tid] = nsecs; > } > > kretprobe:swap_readpage > /@start[tid]/ > { > @us[comm] = hist((nsecs - @start[tid]) / 1000); > delete(@start[tid]); > }
