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From:   =?UTF-8?Q?Micha=C5=82_Kazior?= <kazikcz@gmail.com>
Date:   Fri, 26 Apr 2019 15:44:59 +0200
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Subject: Re: [PATCHv2] ath10k: Add wrapper function to ath10k debug
To:     Venkateswara Naralasetty <vnaralas@codeaurora.org>
Cc:     ath10k@lists.infradead.org,
        linux-wireless <linux-wireless@vger.kernel.org>,
        Kan Yan <kyan@chromium.org>
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On Fri, 26 Apr 2019 at 14:58, Venkateswara Naralasetty
<vnaralas@codeaurora.org> wrote:
>
> ath10k_dbg() is called in ath10k_process_rx() with huge set of arguments
> which is causing CPU overhead even when debug_mask is not set.
> Good improvement was observed in the receive side performance when call
> to ath10k_dbg() is avoided in the RX path.
[...]

> +/* Avoid calling __ath10k_dbg() if debug_mask is not set and tracing
> + * disabled.
> + */
> +#define ath10k_dbg(ar, dbg_mask, fmt, ...)                     \
> +do {                                                           \
> +       if ((ath10k_debug_mask & dbg_mask) ||                   \
> +           trace_ath10k_log_dbg_enabled())                     \
> +               __ath10k_dbg(ar, dbg_mask, fmt, ##__VA_ARGS__); \
> +} while (0)

Did you consider using jump labels (see include/linux/jump_label.h)?
It's what tracing uses under the hood. I wonder if you could squeeze
out a bit more performance with that? I guess you'd need to add
`struct static_key ath10k_dbg_mask_keys[ATH10K_DBG_MAX]` and re-do
ath10k_debug_mask enum a bit.


Michal