Messages in this thread | | | From | "" <> | Subject | RE: [PATCH v4 0/8] Add hardware prefetch control driver for A64FX and x86 | Date | Fri, 20 May 2022 08:31:49 +0000 |
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Thanks for the comment.
> If this is something to be tuned for specific applications, shouldn't it be a prctl or > similar and part of process context, so different applications can use different > settings (or even a single application depending on what it's doing)? Especially if > writing those sysregs/MSRs is cheap.
> In particular, configuring things separately for different cores feels strange. You'd > then have to pin applications to specific cores to get the benefits, and wouldn't be > able to optimize for multiple applications running simultaneously that need > different prefetch behavior if they share cores.
As you say, this is used for tuning specific applications.
I assume that users using this feature bind an application to a specific core and use it exclusively. This is not only for pfctl, but also to prevent performance from being affected by context switches, etc.
I agree that it is also useful to be able to control in the process context. However, in this case, I think that it is sufficient if it can be provided as a userspace interface which expresses the hardware prefetch register directly, assuming the above usage.
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