linux-kernel - Re: [PATCH v5 12/20] x86: perf: intel

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 22 Oct 2014 17:26:44 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc:	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
	Robert Richter <rric@...nel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Mike Galbraith <efault@....de>,
	Paul Mackerras <paulus@...ba.org>,
	Stephane Eranian <eranian@...gle.com>,
	Andi Kleen <ak@...ux.intel.com>, kan.liang@...el.com,
	adrian.hunter@...el.com, acme@...radead.org
Subject: Re: [PATCH v5 12/20] x86: perf: intel_pt: Intel PT PMU driver

On Mon, Oct 13, 2014 at 04:45:40PM +0300, Alexander Shishkin wrote:
> +static void pt_event_start(struct perf_event *event, int mode)
> +{
> +	struct pt *pt = this_cpu_ptr(&pt_ctx);
> +	struct pt_buffer *buf = perf_get_aux(&pt->handle);
> +
> +	if (pt_is_running() || !buf || pt_buffer_is_full(buf, pt) ||
> +	    pt_config(event)) {
> +		event->hw.state = PERF_HES_STOPPED;
> +		return;
> +	}
> +
> +	ACCESS_ONCE(pt->handle_nmi) = 1;
> +	event->hw.state = 0;
> +
> +	pt_config_buffer(buf->cur->table, buf->cur_idx,
> +			 buf->output_off);
> +	wrmsrl(MSR_IA32_RTIT_STATUS, 0);
> +	pt_config_start(true);
> +}

That's two RTIT_CTL writes, should we not try and merge those?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/