Messages in this thread | | | Date | Tue, 19 May 2015 10:33:55 -0700 (PDT) | From | Vikas Shivappa <> | Subject | Re: [PATCH 2/7] x86/intel_rdt: Adds support for Class of service management |
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On Mon, 18 May 2015, Borislav Petkov wrote:
> On Mon, May 18, 2015 at 08:41:53PM +0200, Thomas Gleixner wrote: >>>>> + } >>>>> + >>>>> + set_bit(0, rdtss_info.closmap); >>>>> + rdt_root_group.clos = 0; >>>>> + ccm = &ccmap[0]; >>>>> + bitmap_set(&ccm->cache_mask, 0, max_cbm_len); >>>>> + ccm->clos_refcnt = 1; >>>>> + >>>>> pr_info("Max bitmask length:%u,Max ClosIds: %u\n", max_cbm_len, >>>>> maxid); >>>> >>>> We surely do not want to sprinkle these all over dmesg. >>> >>> This is just printed once! how is that sprinke all over? - we have a dmsg >>> print for Cache monitoring as well when cqm is enabled. >> >> Sorry, mapped that to the wrong function. Though the message itself is >> horrible. >> >> "Max bitmask length:32,Max ClosIds: 16" >> >> With some taste and formatting applied this would read: >> >> "Max. bitmask length: 32, max. closids: 16" >> >> Can you spot the difference? > > I sure can. > > Also, I'd still like to ask about the usability of that message. What > does it bring us? > > And if the dmesg ring buffer wraps around and it gets overwritten, what > do we do then? > > So basically this message does tell us about some max bitmap length and > so on. IOW, useless, right? > > Can it be read out from CPUID maybe? If so, stuff which is interested in > it can generate it then.
Yes the max bitmask and max closid can be read from cpuid. the presence of rdt and l3 cache alloc is indicated by rdt and cat_l3 in /proc/cpuinfo. So even if this message gets overwritten , user can see the feature enabled in kernel.
Can be modified somthing similar to "Intel cache allocation enabled" as well.
Thanks, Vikas
> > -- > Regards/Gruss, > Boris. > > ECO tip #101: Trim your mails when you reply. > -- >
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