Thanks for elaborating ,I've learned that it's not worth it,i'm turning other ways for performance consideration ,thanks!
2018-07-13 15:33 GMT+08:00 <valdis.kletni...@vt.edu>: > On Fri, 13 Jul 2018 11:02:13 +0800, bing zhu said: > > > I‘m trying to write a simple fs in user space,if memcpy is slower than > > kernel , i think it's unfair,as for only cpu for my task, > > it's a bit of arbitrary ，i just want my task not interrupted during a > > specific time is that possible ? > > Not getting interrupted is an *entirely* different issue than making > memcpy fast. > > Note that in general, systems code should be able to deal with > interruptions > during most parts of the code, and locking used and disabling pre-emption > for > sections of code that can't deal with being interrupted. Remember that if > your > filesystem code turns off interrupts for long enough, you can start losing > things like I/O completions. Fortunately for those who write systems code, > the vast majority of interrupts are totally transparent to the vast > majority > of the kernel code. > > And if you're doing a file system in userspace, you're going to fail to > notice > hundreds or even thousands of interrupts happening. If you don't believe > me, > 'cat /proc/interrupts', and realize that userspace didn't notice *any* of > them > happening. > >
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