diff --git a/debian/patches/extra/0035-ratelimit-don-t-align-wait-time-with-slices.patch b/debian/patches/extra/0035-ratelimit-don-t-align-wait-time-with-slices.patch new file mode 100644 index 0000000..ef8c525 --- /dev/null +++ b/debian/patches/extra/0035-ratelimit-don-t-align-wait-time-with-slices.patch @@ -0,0 +1,47 @@ +From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 +From: Wolfgang Bumiller +Date: Tue, 6 Feb 2018 11:34:34 +0100 +Subject: [PATCH] ratelimit: don't align wait time with slices + +It is possible for rate limited writes to keep overshooting a slice's +quota by a tiny amount causing the slice-aligned waiting period to +effectively halve the rate. + +Signed-off-by: Wolfgang Bumiller +--- + include/qemu/ratelimit.h | 11 +++++------ + 1 file changed, 5 insertions(+), 6 deletions(-) + +diff --git a/include/qemu/ratelimit.h b/include/qemu/ratelimit.h +index 8da1232574..324ff04fe2 100644 +--- a/include/qemu/ratelimit.h ++++ b/include/qemu/ratelimit.h +@@ -35,7 +35,7 @@ typedef struct { + static inline int64_t ratelimit_calculate_delay(RateLimit *limit, uint64_t n) + { + int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); +- uint64_t delay_slices; ++ double delay_slices; + + assert(limit->slice_quota && limit->slice_ns); + +@@ -54,12 +54,11 @@ static inline int64_t ratelimit_calculate_delay(RateLimit *limit, uint64_t n) + return 0; + } + +- /* Quota exceeded. Calculate the next time slice we may start +- * sending data again. */ +- delay_slices = (limit->dispatched + limit->slice_quota - 1) / +- limit->slice_quota; ++ /* Quota exceeded. Wait based on the excess amount and then start a new ++ * slice. */ ++ delay_slices = (double)limit->dispatched / limit->slice_quota; + limit->slice_end_time = limit->slice_start_time + +- delay_slices * limit->slice_ns; ++ (uint64_t)(delay_slices * limit->slice_ns); + return limit->slice_end_time - now; + } + +-- +2.11.0 + diff --git a/debian/patches/series b/debian/patches/series index 167bd80..1a6d69d 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -61,3 +61,4 @@ extra/0031-i386-Add-support-for-SPEC_CTRL-MSR.patch extra/0032-i386-Add-spec-ctrl-CPUID-bit.patch extra/0033-i386-Add-FEAT_8000_0008_EBX-CPUID-feature-word.patch extra/0034-i386-Add-new-IBRS-versions-of-Intel-CPU-models.patch +extra/0035-ratelimit-don-t-align-wait-time-with-slices.patch