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Message-ID: <1352268889-16836-1-git-send-email-Frank.Li@freescale.com> Date: Wed, 7 Nov 2012 14:14:49 +0800 From: Frank Li <Frank.Li@...escale.com> To: <lznuaa@...il.com>, <richardcochran@...il.com>, <shawn.guo@...aro.org>, <linux-arm-kernel@...ts.infradead.or>, <netdev@...r.kernel.org>, <davem@...emloft.net>, <bhutchings@...arflare.com> CC: Frank Li <Frank.Li@...escale.com> Subject: [PATCH 2/2] net: fec: reduce spin lock time in fec_ptp_adjfreq move below calculate out of spin lock section diff = fep->cc.mult; diff *= ppb; diff = div_u64(diff, 1000000000ULL); diff is local variable and not neccesary in spin lock Signed-off-by: Frank Li <Frank.Li@...escale.com> --- drivers/net/ethernet/freescale/fec_ptp.c | 14 ++++++-------- 1 files changed, 6 insertions(+), 8 deletions(-) diff --git a/drivers/net/ethernet/freescale/fec_ptp.c b/drivers/net/ethernet/freescale/fec_ptp.c index 5352140..c40526c 100644 --- a/drivers/net/ethernet/freescale/fec_ptp.c +++ b/drivers/net/ethernet/freescale/fec_ptp.c @@ -145,6 +145,7 @@ static int fec_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb) u64 diff; unsigned long flags; int neg_adj = 0; + u32 mult = FEC_CC_MULT; struct fec_enet_private *fep = container_of(ptp, struct fec_enet_private, ptp_caps); @@ -154,6 +155,10 @@ static int fec_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb) neg_adj = 1; } + diff = mult; + diff *= ppb; + diff = div_u64(diff, 1000000000ULL); + spin_lock_irqsave(&fep->tmreg_lock, flags); /* * dummy read to set cycle_last in tc to now. @@ -161,15 +166,8 @@ static int fec_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb) * timercounter_read. */ timecounter_read(&fep->tc); - fep->cc.mult = FEC_CC_MULT; - diff = fep->cc.mult; - diff *= ppb; - diff = div_u64(diff, 1000000000ULL); - if (neg_adj) - fep->cc.mult -= diff; - else - fep->cc.mult += diff; + fep->cc.mult = neg_adj ? mult - diff : mult + diff; spin_unlock_irqrestore(&fep->tmreg_lock, flags); -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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