On 2024/1/10 14:45, Chunhai Guo wrote: > On 2024/1/9 21:08, Gao Xiang wrote: >> [你通常不会收到来自 [email protected] 的电子邮件。请访问 >> https://aka.ms/LearnAboutSenderIdentification，以了解这一点为什么很重要] >> >> Hi Chunhai, >> >> On 2024/1/9 15:41, Chunhai Guo wrote: >>> Using a global page pool for LZ4 decompression significantly reduces >>> the >>> time spent on page allocation in low memory scenarios. >>> >>> The table below shows the reduction in time spent on page allocation >>> for >>> LZ4 decompression when using a global page pool. The results were >>> obtained from multi-app launch benchmarks on ARM64 Android devices >>> running the 5.15 kernel with an 8-core CPU and 8GB of memory. In the >>> benchmark, we launched 16 frequently-used apps, and the camera app was >>> the last one in each round. The data in the table is the average >>> time of >>> camera app for each round. >>> After using the page pool, there was an average improvement of 150ms in >>> the launch time of the camera app, which was obtained from systrace >>> log. >>> +--------------+---------------+--------------+---------+ >>> | | w/o page pool | w/ page pool | diff | >>> +--------------+---------------+--------------+---------+ >>> | Average (ms) | 3434 | 21 | -99.38% | >>> +--------------+---------------+--------------+---------+ >>> >>> Based on the benchmark logs, 64 pages are sufficient for 95% of >>> scenarios. This value can be adjusted from the module parameter. The >>> default value is 0. >>> >>> This patch currently only supports the LZ4 decompressor, other >>> decompressors will be supported in the next step. >>> >>> Signed-off-by: Chunhai Guo <[email protected]> >> >> This patch looks good to me, yet we're in the merge window for v6.8. >> I will address it after -rc1 is out since no stable tag these days. >> >> Also it would be better to add some results of changing max_distance >> if you have more time to test. > > OK. I will reply to this email when the experiment is finished.
Dear Xiang, The experiment is done and table below shows the results. We can find that a 16k sliding window reduces 38.2% of time used in page allocation for LZ4 decompression compared to a 64k sliding window. However, using a global page pool is still far better than both of them. +--------------+---------------+--------------+---------+ | | 64k window | 16k window | diff | +--------------+---------------+--------------+---------+ | Average (ms) | 3364 | 2079 | -38.2% | +--------------+---------------+--------------+---------+ Thanks, > > Thanks. > >> >> Thanks, >> Gao Xiang > >
