linux-kernel - Re: [PATCH V4 4/8] perf/x86/intel/uncore: add new data structures for free running counters

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Date:   Sun, 14 Jan 2018 21:50:35 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Kan Liang <kan.liang@...el.com>
cc:     peterz@...radead.org, mingo@...hat.com,
        linux-kernel@...r.kernel.org, acme@...nel.org, eranian@...gle.com,
        ak@...ux.intel.com
Subject: Re: [PATCH V4 4/8] perf/x86/intel/uncore: add new data structures
 for free running counters

On Thu, 2 Nov 2017, kan.liang@...el.com wrote:
> +/*
> + * Free running counter is similar as fixed counter, except it is read-only
> + * and always active when the uncore box is powered up.
> + *
> + * Here are the rules which are used to encode the event for free running
> + * counter.
> + * - The event for free running counter has the same event code 0xff as
> + *   the event for fixed counter.
> + * - The umask of the event starts from 0x10. The umask which is less
> + *   than 0x10 is reserved for the event of fixed counter.
> + * - The free running counters can be divided into different types according
> + *   to the MSR location, bit width or definition. The start point of the
> + *   umask for different type has 0x10 offset.
> + *
> + * For example, there are three types of IIO free running counters on Skylake
> + * server, IO CLOCKS counters, BANDWIDTH counters and UTILIZATION counters.
> + * The event code for all the free running counters is 0xff.
> + * 'ioclk' is the first counter of IO CLOCKS. IO CLOCKS is the first type,
> + * which umask starts from 0x10.
> + * So 'ioclk' is encoded as event=0xff,umask=0x10
> + * 'bw_in_port2' is the third counter of BANDWIDTH counters. BANDWIDTH is
> + * the second type, which umask starts from 0x20.
> + * So 'bw_in_port2' is encoded as event=0xff,umask=0x22
> + */
> +static inline unsigned int uncore_freerunning_idx(u64 config)
> +{
> +	return ((config >> 8) & 0xf);
> +}
> +
> +#define UNCORE_FREERUNNING_UMASK_START		0x10
> +static inline unsigned int uncore_freerunning_type(u64 config)

Groan. I asked that before that you please stop glueing defines right in
front of a function declaration w/o any visible space. Is it that hard to
read and address _ALL_ review comments?

> +{
> +	return ((((config >> 8) - UNCORE_FREERUNNING_UMASK_START) >> 4) & 0xf);
> +}

Other than that this looks reasonable.