Hello Qiao, >> On 06/10/2015 02:06 PM, Atsushi Kumagai wrote: >>> Hello Zhou, >>> > >Hello Atsushi, > >>>> This patch set implements parallel processing by means of multiple threads. >>>> With this patch set, it is available to use multiple threads to read >>>> and compress pages. This parallel process will save time. >>>> This feature only supports creating dumpfile in kdump-compressed format from >>>> vmcore in kdump-compressed format or elf format. Currently, sadump and >>>> xen kdump are not supported. >>> >>> makedumpfile already has a parallel processing feature (--split), >>> it parallelizes not only page compression but also disk i/o, so >>> I think --split includes what you want to do by this patch. >>> >>> In what case do you think this patch will be effective, what is >>> the advantage of this patch ? > >Since commit 428a5e99eea929639ab9c761f33743f78a961b1a(kdumpctl: Pass >disable_cpu_apicid to kexec of capture kernel) has been merged. It is possible for >us to use multiple cpus in 2nd kernel. > >Using multiple threads is trying to take advantage of multiple cpus in 2nd kernel. >Since memory becomes bigger and bigger, dumping spends more time. Why not take >advantage of multiple cpus? > >OTOH, --split does a lot help to improve performance. But more processes >means more files, saving multiple files and managing those files is not that >convenient. I see, actually I guess some users may feel lazy to use --split since it requires concatenation for analyzing, and it seems that some improvements by using multiple threads can be expected at least in the zlib case. So I agree with the concept. >Multiple threads do have some merit in improving performance. And later, as zhou >said, we can also try to combine --split with multiple threads to save more time. At first I thought it's enough to modify --split path to generate single vmcore. However, if the compression process is the bottleneck, we should allot multiple cpus to each i/o process when doing parallel i/o. For that reason, it's good to introduce the new feature to create multiple threads in addition to --split. Just one thing, when you make the complete version, please make it on the devel branch because cyclic/non-cyclic codes have been changed from v1.5.8. Thanks Atsushi Kumagai >-- >Regards >Qiao Nuohan > >>> >>> >>> Thanks >>> Atsushi Kumagai >>> >>>> >>>> Qiao Nuohan (11): >>>> Add readpage_kdump_compressed_parallel >>>> Add mappage_elf_parallel >>>> Add readpage_elf_parallel >>>> Add read_pfn_parallel >>>> Add function to initial bitmap for parallel use >>>> Add filter_data_buffer_parallel >>>> Add write_kdump_pages_parallel to allow parallel process >>>> Add write_kdump_pages_parallel_cyclic to allow parallel process in >>>> cyclic_mode >>>> Initial and free data used for parallel process >>>> Make makedumpfile available to read and compress pages parallelly >>>> Add usage and manual about multiple threads process >>>> >>>> Makefile | 2 + >>>> erase_info.c | 29 +- >>>> erase_info.h | 2 + >>>> makedumpfile.8 | 24 + >>>> makedumpfile.c | 1505 +++++++++++++++++++++++++++++++++++++++++++++++++++++++- >>>> makedumpfile.h | 79 +++ >>>> print_info.c | 16 + >>>> 7 files changed, 1652 insertions(+), 5 deletions(-) >>>> >>>> >>>> _______________________________________________ >>>> kexec mailing list >>>> kexec at lists.infradead.org >>>> http://lists.infradead.org/mailman/listinfo/kexec >> >>
