| Message ID | 20240216-stmmac_stats-v1-1-7065fa4613f8@axis.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | net: stmmac: mmc_core: Assign, don't add interrupt registers | expand |
On 2/16/24 07:24, Jesper Nilsson wrote: > The MMC IPC interrupt status and interrupt mask registers are of > little use as Ethernet statistics, but incrementing counters > based on the current interrupt and interrupt mask registers > makes them worse than useless. > > For example, if the interrupt mask is set to 0x08420842, > the current code will increment by that amount each iteration, > leading to the following sequence of nonsense: > > mmc_rx_ipc_intr_mask: 969816526 > mmc_rx_ipc_intr_mask: 1108361744 > > Change the increment to a straight assignment to make the > statistics at least nominally useful. > > Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com> > --- > drivers/net/ethernet/stmicro/stmmac/mmc_core.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/ethernet/stmicro/stmmac/mmc_core.c b/drivers/net/ethernet/stmicro/stmmac/mmc_core.c > index 6a7c1d325c46..6051a22b3cec 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/mmc_core.c > +++ b/drivers/net/ethernet/stmicro/stmmac/mmc_core.c > @@ -280,8 +280,8 @@ static void dwmac_mmc_read(void __iomem *mmcaddr, struct stmmac_counters *mmc) > mmc->mmc_rx_vlan_frames_gb += readl(mmcaddr + MMC_RX_VLAN_FRAMES_GB); > mmc->mmc_rx_watchdog_error += readl(mmcaddr + MMC_RX_WATCHDOG_ERROR); > /* IPC */ > - mmc->mmc_rx_ipc_intr_mask += readl(mmcaddr + MMC_RX_IPC_INTR_MASK); > - mmc->mmc_rx_ipc_intr += readl(mmcaddr + MMC_RX_IPC_INTR); > + mmc->mmc_rx_ipc_intr_mask = readl(mmcaddr + MMC_RX_IPC_INTR_MASK); > + mmc->mmc_rx_ipc_intr = readl(mmcaddr + MMC_RX_IPC_INTR); So in premise I agree with the patch, that incrementing those is not the right way to go about them. However these registers are currently provided as part of the statistics set, but they should instead be accessed via the register dumping method. In either case you will get at best a snapshot of those two registers at any given time and I suppose this can help diagnose a stuck RX condition, but not much more than that.
On Fri, Feb 16, 2024 at 09:13:51AM -0800, Florian Fainelli wrote: > On 2/16/24 07:24, Jesper Nilsson wrote: > > The MMC IPC interrupt status and interrupt mask registers are of > > little use as Ethernet statistics, but incrementing counters > > based on the current interrupt and interrupt mask registers > > makes them worse than useless. > > > > For example, if the interrupt mask is set to 0x08420842, > > the current code will increment by that amount each iteration, > > leading to the following sequence of nonsense: > > > > mmc_rx_ipc_intr_mask: 969816526 > > mmc_rx_ipc_intr_mask: 1108361744 > > > > Change the increment to a straight assignment to make the > > statistics at least nominally useful. > > > > Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com> > > --- > > drivers/net/ethernet/stmicro/stmmac/mmc_core.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/mmc_core.c b/drivers/net/ethernet/stmicro/stmmac/mmc_core.c > > index 6a7c1d325c46..6051a22b3cec 100644 > > --- a/drivers/net/ethernet/stmicro/stmmac/mmc_core.c > > +++ b/drivers/net/ethernet/stmicro/stmmac/mmc_core.c > > @@ -280,8 +280,8 @@ static void dwmac_mmc_read(void __iomem *mmcaddr, struct stmmac_counters *mmc) > > mmc->mmc_rx_vlan_frames_gb += readl(mmcaddr + MMC_RX_VLAN_FRAMES_GB); > > mmc->mmc_rx_watchdog_error += readl(mmcaddr + MMC_RX_WATCHDOG_ERROR); > > /* IPC */ > > - mmc->mmc_rx_ipc_intr_mask += readl(mmcaddr + MMC_RX_IPC_INTR_MASK); > > - mmc->mmc_rx_ipc_intr += readl(mmcaddr + MMC_RX_IPC_INTR); > > + mmc->mmc_rx_ipc_intr_mask = readl(mmcaddr + MMC_RX_IPC_INTR_MASK); > > + mmc->mmc_rx_ipc_intr = readl(mmcaddr + MMC_RX_IPC_INTR); > > So in premise I agree with the patch, that incrementing those is not the > right way to go about them. However these registers are currently provided > as part of the statistics set, but they should instead be accessed via the > register dumping method. > > In either case you will get at best a snapshot of those two registers at any > given time and I suppose this can help diagnose a stuck RX condition, but > not much more than that. Could you please clarify why do those CSRs state need to be exposed in the statistics anyway? Who would need such information really? Wouldn't that be better to just drop the stmmac_counters::{mmc_rx_ipc_intr_mask,mmc_rx_ipc_intr} fields? Is it because of the statistics nodes are a kind of kernel ABI? Even in that case I don't see much reason to support something that has been absolutely useless so far seeing the nodes currently returning basically some random values. -Serge(y) > -- > Florian > >
On Fri, Feb 16, 2024 at 09:13:51AM -0800, Florian Fainelli wrote: > So in premise I agree with the patch, that incrementing those is not the > right way to go about them. However these registers are currently provided > as part of the statistics set, but they should instead be accessed via the > register dumping method. You mean extending the dump register code to dump the MAC Management Counter registers that are not counters? From what I understand it's only the Rx and Tx interrupt and interrupt mask registers that aren't counters. Oh, and the MMC control register itself? To be honest, I don't think their use can justify the code churn. > In either case you will get at best a snapshot of those two registers at any > given time and I suppose this can help diagnose a stuck RX condition, but > not much more than that. Yeah, their use is very doubtful. For me, they only introduce more nonsense data in my logs. The Rx registers looks to have been added in the first version of the MMC back in 2011, but the Tx registers never was. In commit 1c901a46d57 Giuseppe mentions the MMC interrupts as something to add later (if actually useful). So Serge's suggestion to drop the entries completely is actually quite attractive. > Florian /^JN - Jesper Nilsson
On 2/19/2024 2:40 AM, Jesper Nilsson wrote: > On Fri, Feb 16, 2024 at 09:13:51AM -0800, Florian Fainelli wrote: >> So in premise I agree with the patch, that incrementing those is not the >> right way to go about them. However these registers are currently provided >> as part of the statistics set, but they should instead be accessed via the >> register dumping method. > > You mean extending the dump register code to dump the MAC Management Counter > registers that are not counters? Yes that is what I meant. > From what I understand it's only the Rx and Tx interrupt and interrupt mask > registers that aren't counters. Oh, and the MMC control register itself? > > To be honest, I don't think their use can justify the code churn. Fair enough, it really depends whether they are actually useful in troubleshooting or not. > >> In either case you will get at best a snapshot of those two registers at any >> given time and I suppose this can help diagnose a stuck RX condition, but >> not much more than that. > > Yeah, their use is very doubtful. For me, they only introduce more nonsense > data in my logs. > > The Rx registers looks to have been added in the first version of the MMC > back in 2011, but the Tx registers never was. > In commit 1c901a46d57 Giuseppe mentions the MMC interrupts as something to > add later (if actually useful). > > So Serge's suggestion to drop the entries completely is actually quite attractive. No concerns from me to drop them, not much value in having inaccurate information.
On Mon, 2024-02-19 at 11:40 +0100, Jesper Nilsson wrote: > On Fri, Feb 16, 2024 at 09:13:51AM -0800, Florian Fainelli wrote: > > So in premise I agree with the patch, that incrementing those is not the > > right way to go about them. However these registers are currently provided > > as part of the statistics set, but they should instead be accessed via the > > register dumping method. > > You mean extending the dump register code to dump the MAC Management Counter > registers that are not counters? > > From what I understand it's only the Rx and Tx interrupt and interrupt mask > registers that aren't counters. Oh, and the MMC control register itself? > > To be honest, I don't think their use can justify the code churn. > > > In either case you will get at best a snapshot of those two registers at any > > given time and I suppose this can help diagnose a stuck RX condition, but > > not much more than that. > > Yeah, their use is very doubtful. For me, they only introduce more nonsense > data in my logs. > > The Rx registers looks to have been added in the first version of the MMC > back in 2011, but the Tx registers never was. > In commit 1c901a46d57 Giuseppe mentions the MMC interrupts as something to > add later (if actually useful). > > So Serge's suggestion to drop the entries completely is actually quite attractive. Please, go ahead and drop such entries. Thank! Paolo
diff --git a/drivers/net/ethernet/stmicro/stmmac/mmc_core.c b/drivers/net/ethernet/stmicro/stmmac/mmc_core.c index 6a7c1d325c46..6051a22b3cec 100644 --- a/drivers/net/ethernet/stmicro/stmmac/mmc_core.c +++ b/drivers/net/ethernet/stmicro/stmmac/mmc_core.c @@ -280,8 +280,8 @@ static void dwmac_mmc_read(void __iomem *mmcaddr, struct stmmac_counters *mmc) mmc->mmc_rx_vlan_frames_gb += readl(mmcaddr + MMC_RX_VLAN_FRAMES_GB); mmc->mmc_rx_watchdog_error += readl(mmcaddr + MMC_RX_WATCHDOG_ERROR); /* IPC */ - mmc->mmc_rx_ipc_intr_mask += readl(mmcaddr + MMC_RX_IPC_INTR_MASK); - mmc->mmc_rx_ipc_intr += readl(mmcaddr + MMC_RX_IPC_INTR); + mmc->mmc_rx_ipc_intr_mask = readl(mmcaddr + MMC_RX_IPC_INTR_MASK); + mmc->mmc_rx_ipc_intr = readl(mmcaddr + MMC_RX_IPC_INTR); /* IPv4 */ mmc->mmc_rx_ipv4_gd += readl(mmcaddr + MMC_RX_IPV4_GD); mmc->mmc_rx_ipv4_hderr += readl(mmcaddr + MMC_RX_IPV4_HDERR);
The MMC IPC interrupt status and interrupt mask registers are of little use as Ethernet statistics, but incrementing counters based on the current interrupt and interrupt mask registers makes them worse than useless. For example, if the interrupt mask is set to 0x08420842, the current code will increment by that amount each iteration, leading to the following sequence of nonsense: mmc_rx_ipc_intr_mask: 969816526 mmc_rx_ipc_intr_mask: 1108361744 Change the increment to a straight assignment to make the statistics at least nominally useful. Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com> --- drivers/net/ethernet/stmicro/stmmac/mmc_core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- base-commit: 0dd3ee31125508cd67f7e7172247f05b7fd1753a change-id: 20240216-stmmac_stats-e3561d460d0e Best regards,