Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751773AbbEGOUr (ORCPT ); Thu, 7 May 2015 10:20:47 -0400 Received: from mail.fireflyinternet.com ([87.106.93.118]:62325 "EHLO fireflyinternet.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751384AbbEGOUm (ORCPT ); Thu, 7 May 2015 10:20:42 -0400 X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Date: Thu, 7 May 2015 15:20:09 +0100 From: Chris Wilson To: Robert Bragg Cc: intel-gfx@lists.freedesktop.org, Peter Zijlstra , David Airlie , linux-api@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Ingo Molnar , Paul Mackerras , Arnaldo Carvalho de Melo , Daniel Vetter Subject: Re: [Intel-gfx] [RFC PATCH 03/11] perf: Add PERF_EVENT_IOC_FLUSH ioctl Message-ID: <20150507142009.GX22099@nuc-i3427.alporthouse.com> Mail-Followup-To: Chris Wilson , Robert Bragg , intel-gfx@lists.freedesktop.org, Peter Zijlstra , David Airlie , linux-api@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Ingo Molnar , Paul Mackerras , Arnaldo Carvalho de Melo , Daniel Vetter References: <1431008154-6833-1-git-send-email-robert@sixbynine.org> <1431008154-6833-4-git-send-email-robert@sixbynine.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1431008154-6833-4-git-send-email-robert@sixbynine.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1517 Lines: 40 On Thu, May 07, 2015 at 03:15:46PM +0100, Robert Bragg wrote: > To allow for pmus that may have internal buffering (e.g. the hardware > itself writes out data to its own circular buffer which is only > periodically forwarded to userspace via perf) this ioctl enables > userspace to explicitly ensure it has received all samples before a > point in time. > > Signed-off-by: Robert Bragg > --- > include/linux/perf_event.h | 7 +++++++ > include/uapi/linux/perf_event.h | 1 + > kernel/events/core.c | 5 +++++ > 3 files changed, 13 insertions(+) > > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index 1af35b4..69a0cb9 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -266,6 +266,13 @@ struct pmu { > * flush branch stack on context-switches (needed in cpu-wide mode) > */ > void (*flush_branch_stack) (void); > + > + /* > + * Flush buffered samples (E.g. for pmu hardware that writes samples to > + * some intermediate buffer) userspace may need to explicitly ensure > + * such samples have been forwarded to perf. > + */ > + void (*flush) (struct perf_event *event); /*optional */ void return? -Chris -- Chris Wilson, Intel Open Source Technology Centre -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/