Hello Luis, thank you for the patch!
On 11/06/2020 00:46, Luis Alberto Herrera wrote: > This change reverts aba3a882a178: "mtd: spi-nor: intel: provide a range > for poll_timout". That change introduces a performance regression when > reading sequentially from flash. Logging calls to intel_spi_read without > this change we get: > > Start MTD read > [ 20.045527] intel_spi_read(from=1800000, len=400000) > [ 20.045527] intel_spi_read(from=1800000, len=400000) > [ 282.199274] intel_spi_read(from=1c00000, len=400000) > [ 282.199274] intel_spi_read(from=1c00000, len=400000) > [ 544.351528] intel_spi_read(from=2000000, len=400000) > [ 544.351528] intel_spi_read(from=2000000, len=400000) > End MTD read > > With this change: > > Start MTD read > [ 21.942922] intel_spi_read(from=1c00000, len=400000) > [ 21.942922] intel_spi_read(from=1c00000, len=400000) > [ 23.784058] intel_spi_read(from=2000000, len=400000) > [ 23.784058] intel_spi_read(from=2000000, len=400000) > [ 25.625006] intel_spi_read(from=2400000, len=400000) > [ 25.625006] intel_spi_read(from=2400000, len=400000) > End MTD read I've performed my testing as well and got the following results: Vanilla Linux 4.9 (i.e. before the introduction of the offending patch): dd if=/dev/flash/by-name/XXX of=/dev/null bs=4k 1280+0 records in 1280+0 records out 5242880 bytes (5.2 MB, 5.0 MiB) copied, 3.91981 s, 1.3 MB/s Vanilla 4.19 (i.e. with offending patch): dd if=/dev/flash/by-name/XXX of=/dev/null bs=4k 1280+0 records in 1280+0 records out 5242880 bytes (5.2 MB, 5.0 MiB) copied, 6.70891 s, 781 kB/s 4.19 + revert: dd if=/dev/flash/by-name/XXX of=/dev/null bs=4k 1280+0 records in 1280+0 records out 5242880 bytes (5.2 MB, 5.0 MiB) copied, 3.90503 s, 1.3 MB/s Therefore it looks good from my PoV: Tested-by: Alexander Sverdlin <alexander.sverd...@gmail.com> > Signed-off-by: Luis Alberto Herrera <luisalbe...@google.com> > Acked-by: Mika Westerberg <mika.westerb...@linux.intel.com> > --- > drivers/mtd/spi-nor/controllers/intel-spi.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/mtd/spi-nor/controllers/intel-spi.c > b/drivers/mtd/spi-nor/controllers/intel-spi.c > index 61d2a0ad2131..2b89361a0d3a 100644 > --- a/drivers/mtd/spi-nor/controllers/intel-spi.c > +++ b/drivers/mtd/spi-nor/controllers/intel-spi.c > @@ -292,7 +292,7 @@ static int intel_spi_wait_hw_busy(struct intel_spi *ispi) > u32 val; > > return readl_poll_timeout(ispi->base + HSFSTS_CTL, val, > - !(val & HSFSTS_CTL_SCIP), 40, > + !(val & HSFSTS_CTL_SCIP), 0, > INTEL_SPI_TIMEOUT * 1000); > } > > @@ -301,7 +301,7 @@ static int intel_spi_wait_sw_busy(struct intel_spi *ispi) > u32 val; > > return readl_poll_timeout(ispi->sregs + SSFSTS_CTL, val, > - !(val & SSFSTS_CTL_SCIP), 40, > + !(val & SSFSTS_CTL_SCIP), 0, > INTEL_SPI_TIMEOUT * 1000); > } > > -- Best regards, Alexander Sverdlin.
