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Groups > linux.kernel > #1509320

[PATCH 4.4 021/112] perf intel-pt: Fix MTC timestamp calculation for large MTC periods

From Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups linux.kernel
Subject [PATCH 4.4 021/112] perf intel-pt: Fix MTC timestamp calculation for large MTC periods
Date 2016-10-26 15:10 +0200
Message-ID <sww7T-49u-23@gated-at.bofh.it> (permalink)
References <swvER-3Eq-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Adrian Hunter <adrian.hunter@intel.com>

commit 3bccbe20f6d188ce7b00326e776b745cfd35b10a upstream.

The MTC packet provides a 8-bit slice of CTC which is related to TSC by
the TMA packet, however the TMA packet only provides the lower 16 bits
of CTC.  If mtc_shift > 8 then some of the MTC bits are not in the CTC
provided by the TMA packet. Fix-up the last_mtc calculated from the TMA
packet by copying the missing bits from the current MTC assuming the
least difference between the two, and that the current MTC comes after
last_mtc.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1475062896-22274-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 tools/perf/util/intel-pt-decoder/intel-pt-decoder.c |   36 ++++++++++++++++++++
 1 file changed, 36 insertions(+)

--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -89,6 +89,7 @@ struct intel_pt_decoder {
 	bool pge;
 	bool have_tma;
 	bool have_cyc;
+	bool fixup_last_mtc;
 	uint64_t pos;
 	uint64_t last_ip;
 	uint64_t ip;
@@ -584,10 +585,31 @@ struct intel_pt_calc_cyc_to_tsc_info {
 	uint64_t        tsc_timestamp;
 	uint64_t        timestamp;
 	bool            have_tma;
+	bool            fixup_last_mtc;
 	bool            from_mtc;
 	double          cbr_cyc_to_tsc;
 };
 
+/*
+ * MTC provides a 8-bit slice of CTC but the TMA packet only provides the lower
+ * 16 bits of CTC. If mtc_shift > 8 then some of the MTC bits are not in the CTC
+ * provided by the TMA packet. Fix-up the last_mtc calculated from the TMA
+ * packet by copying the missing bits from the current MTC assuming the least
+ * difference between the two, and that the current MTC comes after last_mtc.
+ */
+static void intel_pt_fixup_last_mtc(uint32_t mtc, int mtc_shift,
+				    uint32_t *last_mtc)
+{
+	uint32_t first_missing_bit = 1U << (16 - mtc_shift);
+	uint32_t mask = ~(first_missing_bit - 1);
+
+	*last_mtc |= mtc & mask;
+	if (*last_mtc >= mtc) {
+		*last_mtc -= first_missing_bit;
+		*last_mtc &= 0xff;
+	}
+}
+
 static int intel_pt_calc_cyc_cb(struct intel_pt_pkt_info *pkt_info)
 {
 	struct intel_pt_decoder *decoder = pkt_info->decoder;
@@ -617,6 +639,11 @@ static int intel_pt_calc_cyc_cb(struct i
 			return 0;
 
 		mtc = pkt_info->packet.payload;
+		if (decoder->mtc_shift > 8 && data->fixup_last_mtc) {
+			data->fixup_last_mtc = false;
+			intel_pt_fixup_last_mtc(mtc, decoder->mtc_shift,
+						&data->last_mtc);
+		}
 		if (mtc > data->last_mtc)
 			mtc_delta = mtc - data->last_mtc;
 		else
@@ -685,6 +712,7 @@ static int intel_pt_calc_cyc_cb(struct i
 
 		data->ctc_delta = 0;
 		data->have_tma = true;
+		data->fixup_last_mtc = true;
 
 		return 0;
 
@@ -751,6 +779,7 @@ static void intel_pt_calc_cyc_to_tsc(str
 		.tsc_timestamp  = decoder->tsc_timestamp,
 		.timestamp      = decoder->timestamp,
 		.have_tma       = decoder->have_tma,
+		.fixup_last_mtc = decoder->fixup_last_mtc,
 		.from_mtc       = from_mtc,
 		.cbr_cyc_to_tsc = 0,
 	};
@@ -1241,6 +1270,7 @@ static void intel_pt_calc_tma(struct int
 	}
 	decoder->ctc_delta = 0;
 	decoder->have_tma = true;
+	decoder->fixup_last_mtc = true;
 	intel_pt_log("CTC timestamp " x64_fmt " last MTC %#x  CTC rem %#x\n",
 		     decoder->ctc_timestamp, decoder->last_mtc, ctc_rem);
 }
@@ -1255,6 +1285,12 @@ static void intel_pt_calc_mtc_timestamp(
 
 	mtc = decoder->packet.payload;
 
+	if (decoder->mtc_shift > 8 && decoder->fixup_last_mtc) {
+		decoder->fixup_last_mtc = false;
+		intel_pt_fixup_last_mtc(mtc, decoder->mtc_shift,
+					&decoder->last_mtc);
+	}
+
 	if (mtc > decoder->last_mtc)
 		mtc_delta = mtc - decoder->last_mtc;
 	else

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[PATCH 4.4 000/112] 4.4.28-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 14:50 +0200
  [PATCH 4.4 061/112] NFSv4: Dont report revoked delegations as valid in nfs_have_delegation() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 084/112] irqchip/gicv3: Handle loop timeout proper Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 028/112] powerpc/powernv: Use CPU-endian hub diag-data type in pnv_eeh_get_and_dump_hub_diag() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 051/112] ALSA: hda - Fix a failure of micmute led when having multi adcs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 074/112] Clarify locking of cifs file and tcon structures and make more granular Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 027/112] powerpc/powernv: Pass CPU-endian PE number to opal_pci_eeh_freeze_clear() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 071/112] fs/super.c: fix race between freeze_super() and thaw_super() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 077/112] SMB3: GUIDs should be constructed as random but valid uuids Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 019/112] perf intel-pt: Fix snapshot overlap detection decoder errors Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 024/112] dm mpath: check if paths request_queue is dying in activate_path() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 072/112] cifs: Limit the overall credit acquired Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 070/112] arc: dont leak bits of kernel stack into coredump Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 057/112] Input: i8042 - skip selftest on ASUS laptops Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 054/112] lib: move strtobool() to kstrtobool() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 037/112] zfcp: restore: Dont use 0 to indicate invalid LUN in rec trace Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 058/112] Input: elantech - force needed quirks on Fujitsu H760 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 055/112] lib: update single-char callers of strtobool() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 060/112] sunrpc: fix write space race causing stalls Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 053/112] MIPS: ptrace: Fix regs_return_value for kernel context Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 056/112] lib: add "on"/"off" support to kstrtobool Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 010/112] platform: dont return 0 from platform_get_irq[_byname]() on error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 047/112] [media] mb86a20s: fix the locking logic Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 022/112] dm: mark request_queue dead before destroying the DM device Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 021/112] perf intel-pt: Fix MTC timestamp calculation for large MTC periods Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 043/112] scsi: zfcp: spin_lock_irqsave() is not nestable Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 017/112] pstore/ram: Use memcpy_toio instead of memcpy Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 041/112] zfcp: fix payload trace length for SAN request&response Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 050/112] [media] cx231xx: fix GPIOs for Pixelview SBTVD hybrid Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 049/112] [media] cx231xx: dont return error on success Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 044/112] fbdev/efifb: Fix 16 color palette entry calculation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 048/112] [media] mb86a20s: fix demod settings Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 015/112] pstore/ramoops: fixup driver removal Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 032/112] ubi: Deal with interrupted erasures in WL Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 046/112] ovl: copy_up_xattr(): use strnlen Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 036/112] zfcp: retain trace level for SCSI and HBA FSF response records Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 013/112] parisc: Fix kernel memory layout regarding position of __gp Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 011/112] cpufreq: intel_pstate: Fix unsafe HWP MSR access Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 038/112] zfcp: trace on request for open and close of WKA port Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 035/112] zfcp: close window with unblocked rport during rport gone Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 034/112] zfcp: fix ELS/GS request&response length for hardware data router Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 042/112] zfcp: trace full payload of all SAN records (req,resp,iels) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 040/112] zfcp: fix D_ID field with actual value on tracing SAN responses Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 045/112] ovl: Fix info leak in ovl_lookup_temp() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 033/112] zfcp: fix fc_host port_type with NPIV Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  Re: [PATCH 4.4 000/112] 4.4.28-stable review Shuah Khan <shuah.kh@samsung.com> - 2016-10-26 20:50 +0200
  Re: [PATCH 4.4 000/112] 4.4.28-stable review Guenter Roeck <linux@roeck-us.net> - 2016-10-26 23:50 +0200

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